Quick questions:
How do you get crystals?
What do you get for completing character missions? (speaking of which, you DO have to complete said missions with the specific character shown beside it, correct? So if you didn't bring that character, you cant do that mission?)
Do not all characters have 4 costumes? Because I haven't gotten a 3rd for some characters despite them being leveled up and played a lot.
Raise the relationship between the team you're using and the person giving you the mission. Increased relationships only really matter between your team and for certain level unlocks
Only characters who've been in previous iterations have 4 costumes. Someone from Samurai Warriors 3 will have two costumes, but someone from Samurai Warriors 1 will have 4 costumes. Same with DW