Help on Team Creation

Wel you seem like fresh into the game so I'd like to suggest you start by re-rolling until you get a good hero or a decent iv set for one you really like. By deleting and re downloading the app you reset your file and after doing those first 2-3 prologue maps you can have about 20 orbs to summon from any of the 3 current banners to try and score a hero from there or just someone you like and then build from there honestly. Iv stats are important to check for all heroes you summon at lv 1 so you can tell how good they are, how to build them, or if they are inheritance fodder.

Got a list of your favorite handful of fire emblem characters you want to try for?

If you are that new to the game, worrying about team creation or builds is premature. Your units need some levels first.

In my opinion, a team of Hana, Setsuna, Sully, and Alm can get the job done until you get better units

Agreed with the others: it's too early to really worry about team comp. Alm is a good starting unit with his attack power at least. Hana's L&D will be valuable down the line, but is probably not a long-term solution. I'd actually use the starter units for a while and put some feathers into getting at least Anna and Sharena to 4 stars. You can probably clear a good chunk of the story though with Alm, Sully, Sakura, and Anna or Setsuna.

How the fuck do you have FOUR 5star hero with only 2 summoning xD

The RNG god loves you.
Honestly, just take your five stars heroes, the Campaign will be quite simple, then you summon more heroes and get a balanced team.

Instead of repeating everyone's answer, I just want to say that despite this game giving you very limited recources, knowledge comes from trial and error, and experience, looking at something on paper and actually putting to use in practice is very different. I think making the mistakes of merging that level 13 Lucina into my level 40 one without knowing what IVs were was by far my most painful experience in this game.

To give you my advice though, 5 stars are worth keeping and leveling, 4 stars are worth keeping, 3 stars are for inheritance and potentially worth upgrading with good IVs, and finally the three "starters"; Sharena, Anna, Alfonse are worth using and upgrading since you only get one of each, they're all strong in their own right, and they get cycled through as arena bonus heroes.

Four 5* heroes this soon is better than I had when I started out! I wouldn't recommend starting over. ;)

Here's my suggestion from what you have right now:

ALM, because he's well-rounded and Falchion heals him by 10 HP every 3rd turn. Hana is good too, but tricky to play because she's all attack and no defense.

SHARENA, a solid lancer who's better than the other 2 blues you have right now. She'll serve you well in the long run too: all 3 Askrans can get you bonus points in certain Arena seasons and Tempest Trials.

SETSUNA is one of the best archers, and is leagues better than Virion.

Neither of your Greens are very good, unfortunately. If you like using Anna, stick with her. Otherwise, try Gunter for a while.

Your team will change and grow as you summon more heroes, so don't be too distressed about working with you have right now. :)

Hope this helps, and good luck!