Play with a friend or play with strangers but one thing is for sure, you have to win.

Outfit	How to unlock
Ada EX 2	Survivors: Win 5x.
Chris EX 2	Survivors: Win 10x.
Helena EX 2	Survivors: Win 10x.
Jake EX 2	Team Survivors: Win 5x.
Leon EX 2	Survivors: Win 5x.
Sherry EX 2	Team Survivors: Win 10x.