Originally Posted by blazing hellion
Note, I THINK you can unlock a costume on tag for the first character. I played kasumi/hitomi, I didn't have any costume unlocked for either of them and I unlocked one only for kasumi, then did the next difficulty but selected hitomi/kasumi. Got one for hitomi. I might have just missed it though so don't quote me.
You are right, you can unlock costume by doing Tag courses. I always do that for every character. For me, the following courses are the best way to unlock costumes : Arcade Rookie, Tag Arcade Rookie, Tag Time Attack Rookie, and Rookie Survival.
I prefer the Tag courses since its only 5 figths instead of 8 when solo. Save quite a lot of time.