Choose Your Legends 2 in Tier List

It all depends in what you already have, for whales for example B!Ephraim may not appear that appealing since they probably already have many green axe armors at +10, mainly L!Hector.
If i had to rate them for new player this is how i'd rate them:
1- Veronica, she already comes with a complete set, you just need to give her atk+3 or spd+3 in the A slot and you're good to go, her healing with her balm and the wrazzle dazzle combo will be very usefull to clear any early PvE content
2- Hector, he comes with a skillset that can be used even outside armor emblem without any problem, Maltet+bold fighter makes him able to double in both phases and has a power crept DC
3- Celica, she is top 5 as sword unit, her spd+double lion makes her able to quad which is very usefull, but to shine she needs either Firesweep sword or Armorsmashe, which isn't the best for early players who still have to invest feathers elsewhere
4- Ephraim, i rate him as last not because he isn't strong but he needs investment and a armor emblem to shine, if you don't have an armor emblem or tactics you may have trouble activating Garm, and to reach his max potential you alson need to give him DC, which isn't that easy to get

I hope i helped you deciding who to choose, choose Hector if you already summoned Veronica in the banner, if not pick her, she is just so usefull in bit early game but also when you advnce in the game.
In this type of thing don't follow Tier lists, just pick what will be the most usefull for you, B!Ephraim will probably be rated very high in the tier list but he isn't as usefull for new player as the other 3

It's safe to assume that they will all be in tier 1 if that's what you care about.

Who's the best out of them can't really be objectively said imho, because they all have different colors, different roles and mostly different movement types...so the actual ranking will depend on each player.
Personally, I would rank them: Veronica -> Hector -> Celica -> Ephraim.

Gamepress hasnt update CYL2 into the tierlist yet.

Veronica is popular so she chosen more. Even tho I like ephraim, I still picked veronica bc i wanna get an iv'd ephraim.
ephraim is good for armor meta. veronica, our first prf staff, hector emblem, celica is for that nostalgic yet she still has that power!

pretty sure hector and ephraim will dominate the (arena) tier list again

celica's nutty but not amazing, only pick her if you really liked shadows of valentia and want to show character royalty

veronica was definitely the popular pick for plenty of people. pick her if you want a tragic loli to train. she's a pretty interesting support (buffs and debuffs) but might not be as useful in clearing the story.

First of all, welcome.

Second, don't follow the tier lists. They are severely skewed if you're trying to understand which characters have more potential as combatants because the tier list is designed with arena scoring in mind, and arena scoring is an entirely different game that involves spamming as much BST and SP as possible without LOSING combat effectiveness. For example, a lot of builds will use aether and dual rallies or close/distant counter just because these skills cost more SP even though more damaging specials with lower cooldown, positioning assists, and stat- boosting A-skills would help the character more. Similarly, this varies player by player but I would say there are far more interesting options for merge projects for a f2p than Gwendolyn and Effie, but a lot of people go for those two because they have higher BST and therefore score better.

I made a different tier list, also not based on just combat potential but instead on how much game expertise is required to use the unit effectively. It doesn't contain all the characters, but you might like to have a look. https://fireemblem.gamepress.gg/q-a/difficulty-tier-list

As to which of the CYL2 units you should pick, don't go by what others tell you is best or worst. All four are extremely strong, mostly in pretty different ways. I suggested this to one other relatively new player and I think I can repeat it here: just wait to make your pick. These units practically break the game. Learn how to play without them, and then you'll be able to understand what they do and which one you want to free-pick.

Don't pick based on tier list. Ever. Tier lists can really mislead you if you don't know how to read them. Rather, you should pick the unit that fits the content of the game you most care about, the character you most like, or the unit type that would help the most.

IMO, for most players I would pick them in the following order: Veronica->Hector->Celica->Ephraim.

Veronica will have the most long-lasting impact for the most amount of players simply because Wrazzle Dazzle healers are always useful in all game content. Hector and Celica are fairly close in usefulness, as Hector's true value won't be seen until you have an armor team and you can replicate much of what he does with Effie. Meanwhile, Celica is really good and will only get better as new swords are released, but she requires more investment than the others to throw new words onto her. Ephraim... really shouldn't even be a consideration for most. There are just too many green armors, and while he's good, he doesn't really separate himself from a crowded pack.

GamePress usually waits till the next New Heroes/Seasonal Banner, idk why. Best one would be Hector, then Ephraim, then Celica, then Veronica. It’s really close competition though. They’re all great but in the end it comes down to 2 things. 1: Preference, which character do you like the most. 2: Long Term Investment, which one will you invest into the most.