Just curious...

Some nice questions you got there.

1) Probably my bridelia -atk + spd. She was my first 5* and was the first unit I gave a full build. She carried me through so many TT and Arena matches its not even funny. Tho she doesn't get much use these days cuz flier emblem is just awesome and I lack the SI fodder to upgrade her from Quadelia to a Firesweep variante, she's still my favorite unit in my roster.

2) Bridelia -atk +spd, Tana +def - res, W!Tharja+1 +res - spd and P!Azura+1 +spd -hp. Bridelia because of 1), Tana because she's the foundation of my flier emblem team and the main reason I love it so much, Tharja because she's op and her in fight voicelines are hilarious, Azura because she's the ultimate support unit, which often works as the crutch of every random team I throw together

3) Probably BowLyn. She was my cyl unit and I tried to build horseemblem with her and Boy thinking camus or Xander would come back any time soon. Well, I was wrong.

4) The only unused/not fully built units I have lying around were random pity breakers and I honestly would rather start completely over than seeing a 5* peri, luke, karel, sakura or seth

5) Now this is a hard one. I kind of tend to say yes, I'll take the 3 other units instead of Bridelia, just because I'll get more use out of them.

6) I'd take my 4 units over the rest. All 4 of them are units that made teams I built fun to use and would do so again and again.

I am not 100% F2P but I've only bought orbs twice. The first time was for B!Lyn (Got an Innes instead), and the second time was for Tana (Got a Nowi instead). Innes is already long gone (Sold for Fortress Res, so I won't take this skill into account, either) but I'll avoid using Nowi in any of the questions and pretend as though I don't even have her.

1) This is a hard one, either my +2 +Res -Defense Delthea or my +Speed -Defense Quad S!Gaius. These two units have gotten me through so much and although I have units that I have invested in more/are better, I haven't gotten nearly as much use from them as I have from these two. If I really had to choose... I'd have to go with... Delthea. Gaius's role isn't that special and honestly the story of how I got him isn't nearly as insane, so that's my choice.

2) The two meantioned above as well as a +1 Berkut's Lance DC Donnel and a Steady Breath Wo Dao Arden. Both of these units have so much investment and are honest way stronger​ than expected. So my whole team would be Delthea, Gaius, Donnel, Arden. (If I had to choose a green, it would also be B!Ike)

3) A +Attack -HP Sonya I've had since she came out. I used her so much for a long time... And then suddenly... Stopped.

4) I have a habit of building expensive units and then never using them again (One of these is a Fortress Res Deirdre but I'm not counting that). That team would be a +Speed -Hp Katarina with Blade, +Defense -Speed Faye with Guard Bow and Distant Defense, +Defense -Attack Ephraim (There's an obvious reason why I never use him), and that Sonya.

5) Very tough, but I would probably keep the unused units for a couple reasons. One, I could do so much with these units that I definitely couldn't do with Delthea alone and they have roughly the same amount of investment. Two, I've used Delthea so much... It's kinda boring at this point. Starting over with a team of units I never use would actually force me to give them the proper amount of attention they deserve and I think that would be much more fun than just keeping Delthea.

6) Another difficult question. While it somewhat contradicts my last answer, I think I'd have to keep the team and lose everything else. These four units are my bread and butter and I could easily survive with just these four, at least for long enough to build up more five stars again.

I'm not a F2P, i have brought orbs only for 3 banners however, Spring, Christmast and Summer. I will however ignore the units i have gained with brought orbs, even if i might mention them in question 6.

1) In all honesty, it would be my Adult Tiki, she isn't merged or anything, but her IVs of +ATK -DEF are good enough for me and i have some 3* ready to be promoted to 5* in order to merge her. Adult Tiki has a special place in my heart because she was one of the 3* units i had on my team all through the game and was a constant part of my team up until VS Veronica. So i'd deffinitly take her with me if i had to start over.

2) Adult Tiki, Nephenee, M!Robin and Legion.
My M!Robin's built is made as an healer and support so that way i can freely pick a team that hit hard and could need constant healing. Thank to him swaping HP and the like,s he can make sure that Nephenee can always have wrath activating while also keeping her safe if she's put in a situation that could get her killed with low HP, same goes for Legion and his fury. Adult Tiki is a unit that counter from far so she's mostly put against green mage unit and any other physical units that aren't blue. The way i play this game just make it so that team is a perfect starting team for me.

3) My neutral IV Shigure.. He's literally the only unit i haven't played and put in a team other then to sing units i'm grinding. How sad is that?

4) Shigure, Halloween Jakob, Eldigan and Lachesis. Those are the mains units i keep in my roster that aren't fodder material and that i don't use enough or at all.

5) In all honesty, this is really hard because on 1 hand i'd have a decent team but on the other i get to keep a unit that had a lot of memories and have the chance to make more memories with this units which also happen to be one of my favs.. I'll go with 4) for utility. Adult Tiki will be born again as a 3* i'm sure of it.

6) Oh i'd deffinitly rather start over with the units i listed! Even if it mean losing my units i got thank to wasting money. And my Robin Emblem team. :')

I'm not fully F2P but I only spent 40€ once and the Nowi I got therefrom does not appear here.

1) I'd probably take my Brave Lyn (+Atk -Res)+3. I have other very strong units but this is my highest merged nat 5 and she can defeat anything. And she is one unit I wanted and really got although I didn't snipe for her. The other one is my Eldigan. Also she is Summoner Support and has 9999 SP and 3000 Merit so I really use her alot.

2) That's hard stuff, as I have two main teams...
But I'd probably take my Horse Emblem:
Eldigan+2 (+Spd -Def), Camus+1, Cecilia+2 (+Atk -Def) and the mentioned Brave Lyn. This team cleared me any story map, so I owe them one.

3) It's quite hard to define "unused" for me, as I may not have all of my heroes in a team but I use nearly all of them for Arena Assault. At least sometimes.
I guess I can define units under 100 Hero Merit as "unused" then my Bridal Caeda should make the run (+Atk -Res).

4) This Caeda, Anna, Eliwood (+Spd, -Res) and a Gordin (+Atk -Res). None of these ever got any skill by inheritance, Eliwood and Gordin do literally start at 0 (Level, Merit and SP) Actually a good idea to build them as I have to think of it (you see: nothing decent remains unused for long).

5) If I'd really take them with me: yes. Being the only one in the world with Anna+1 sounds funny xD
Back to reality: no. My Brave Lyn is 4 units, those are four units. My Brave Lyn is farily better. And well, I have (nearly) never used those 4 so they don't have a story to tell, as my Brave Lyn has.

6) Tactically: I'd just lose my main Horse Emblem. I could build up my Xander and my second one is ready to fight being only slightly worse. And I still have another Main Team so it would hurt, yes, as I played with my beloved Four Riders for about half a year now and they gave me everything, but even losing them does not destroy my empire. That sounds really cold, does it?
Both choices hurt me a lot. I always lose old friends. If I deleted the other, I'd lose my very first team (so my first 5*, I recall it now, it was Robin), I'd lose my other main team, all my hope for remaining in Tier 20 and somehow a whole year of gaming. Damn, I don't really want to chose, if I consider anything.

1) My Empress Sanaki

2) Sanaki, Then i would make my Boey her lackey (+atk-hp, he is also my team healer and blade user), as blue unit i would take Roderick (+atk-def, he is my charger), and in 4th spot my boiii Azama (+hp-spd) with his endless pain dealing.

3) Also probably Ayra, she is +spd-def, and she is pretty dope, but i dont feel like replacing my empress Sanaki with her. There is also Reinhard i dont use almost at all.

4) Ayra, Rein, BIke and prolly NekoSakura.

5) No, i would not.

6) I dont rly like to start over, i have pretty dope roster im proud of.

I hope it counts, since i have bought whole 10 orbs in desperate chase after Rhajat (still dont have her).

Pure F2P. Been playing since mid-Feb.

1. It'd be my +atk/-spd Effie. She is the literal cornerstone of my Armor Emblem team. Used to have a Brave build on her, then I got into slapping DC on her and bequeathing Berkut's Lance. Looking to invest further on her, so if I'm able to take her with me on a restart, it'd definitely be awesome.

2. The aforementioned Effie, a +spd/-def Olwen that I've gotten long before I pulled her more infamous brother, a +res/-def P!Olivia, and a +spd/-res Ayra.

3. A +5 4* Cherche that I've built from the ground up—Death Blow/Desperation/Fortify Fliers/Heavy Blade, with Galeforce as special.

4. +Atk/-def Delthea, +def/res Ephraim, +atk/def Nino, and the +res/def P!Olivia earlier.

5. It'd be #1, after giving it a LOT of thought.

6. Those four.

Ooh, this looks interesting!

1. Choosing only one unit to keep is incredibly difficult, but after much consideration, I'm going with Azura, +hp -atk. Terrible IVs, yes, but her Sapphire Lance makes her an incredible red check and she's my most-used dancer. She's not exactly my flashiest unit, but most of my best powerhouses would actually be easier to obtain than she would, and given that all the blue dancers are super rare, I'm thinking she's the unit I'd keep.

2. Strange as it seems, if I were bringing a whole team I actually wouldn't bring Azura, I'd bring Ninian instead. She's +spd -atk, and she's inherited (though not fully learned yet) all the skills she needs to be the ultimate Falchion survivor and serve as the only blue on a team, so she's pretty cool, but the real reason I'd bring her over Azura is Fortify Dragons. That's because the next unit I'd bring is Fae. Yes, she'd be easy enough to obtain in a new game, but she took me months to build and I'm not just giving her up. She's +def -hp, merged +1, has a +def refined lightning breath, Fury, and the res +2 seal, so her def/res stats are at 36/36. Run her with Ninian and she reaches 42/42. Between he and Ninian, I swear there is no unit they can't take down; their only fear is Julia with Divine Naga and she's just not that common. Their power is beyond ridiculous and cannot be overstated. Other than those two, I'd bring my neutral B!Lyn (she's amazing and you can't go wrong with her, and bringing her would free me up to pick B!Ike as my new CYL unit) and my +hp -res Lucina. I love Lucina so much, she slots into so many teams and murders so many units. She's been an incredible workhorse for me and was my first unit to max HM. She's been kind of powercreeped by certain other sword users lately, but she's still good and we've been through so much together, I couldn't just leave her behind. (Here we pause to say a prayer for my 4*+10 Nino, TA!Raven F!Robin, and Arvis.)

3. I probably shouldn't count Sigurd as unused, since the only reason he is is because I only just pulled him from the last legendary banner and haven't had the chance to level him fully yet. That said, there really aren't a whole lot of units I'd consider good that I've left unused. The best I've got is probably my 5* +atk -something (not speed) Catria, who I pulled shortly after I started building my +atk Cordelia, and I couldn't think of a reason to justify building both.

4. The above-mentioned Catria, +res -hp Athena, Michalis, and... +hp -spd Sumner Leo, I guess. (He's not Arvis but he could try.)

5. Keeping Azura all the way, not a remotely hard decision for me.

6. This is much harder. I'd lose my most powerful team, but I'd keep my beloved F!Robin, Nino, and Arvis (as well as Azura actually, did I just accidentally game the system?), plus great units like B!Ike and Reinhardt and P!Inigo. It's really tempting to say I'd ditch the four and keep the rest...but I don't think I can do it. I put too much work into Fae, it would be way too painful to keep most of my roster and slog to replace and rebuild her, whereas keeping only those four would feel more like a fresh start and would actually be less painful and more fun overall, I think.

1. Definitely B!Lyn. I got her off the free summon, but she's still amazing.
2. If it has to be a functional team... B!Lyn, +Spd/-Def Blade Cecilia+1 w/ LnD, B!Roy (unfortunately -Spd/+Def, but he has a +3 Spd seal), and (-Atk/+Something Elise)
If it can just be four individual units:
B!Lyn, Cecilia, +Atk/-Res W!Lissa, and my +Spd/-Def (I think) Azura. Regular Azura, not Axura.
3. That's tough. I would probably say my +Spd/-HP Celica, though I would say my +Atk Blarblade Linde is close behind.
4. Celica, Linde (Dark Aura instead of Blarblade), P!Inigo (-Atk/+Def), running Gronnraven, and Masked Marth (Fury Medic)
5. I'd probably just take the B!Lyn.
6. I would keep those four. B!Lyn, Cecilia, and Elise are just really great, and B!Roy would be great if not for his stupid IV.