To unlock the following, complete the following tasks included Deckers, Luchadores and more.

Costume	How to unlock
Cops/SWAT	Finish all Snatch activities for Kinzie.
Deckers	Finish the Assassination (mission 37) from Kinzie that requires you to wear one .
Hos	Finish all Snatch activities for Zimos.
Luchadores	Finish mission 43.
Mascots	Compete all of Professor Genki's S.E.R.C. activities.
Morningstar	Finish mission 29.
National Guard	Finish all Tank Mayhem activities.
Space Saints	Finish mission 47.
Strippers	Finish all Escort activities for Zimos.
Wrestlers	Finish Tiger Escort activities.