1. Can I change attires like masks after saving?
2. I can change Classes in Matches? So it is the same character with his abilitys but change to medic? Or do I change Characters in Matches?
So when I change bodytypes It still is the same Character?
3. Can I change weapons in match?
1. You can change any part of your character's apparel from the main menu option. The only choices that are permanent after saving are face/voice right at the beginning, and if you decide to apply tattoos at any point.
2. From any of your team's command posts, yes. It will be the same character: lets say if you had purchased 5 medic abilities and 2 abilities from Soldier, Engineer & Operative so far, and you hop into a match and play as a medic. Even though all of your abilities are active, even the 6 other class' abilities, since you are playing as a medic you ONLY have access to the 5 medic abilities... and any universal abilities you may have purchased too, like increased health. Once you pick a character, you are stuck with that character for the match. You can change bodytypes in the same menu as apparel,
not mid-match.
3. Yes, from friendly Command Posts. The layout/process http://www.youtube.com/watch?v=l_CykYOy6Lw (which might show you some other nifty things you didn't know, too).
Hope that helped!