Successfully complete 100% of the side missions to unlock the Brassiere and Bikini 2 costumes. Successfully complete 100% of the Blacklist to unlock the Brassiere 4 and Sarong costumes. Interrogate the following characters to unlock an alternate costume at the indicated location:

Rag Shack

Crowe in Chapter 2; Abandon Subway
Ralph in Chapter 2; The Hole
Diana in Chapter 3; Railroad Yard
Freddie in Chapter 3; Hospital
Mike in Chapter 3; Station Zone
Dirk in Chapter 5; Station Zone
Freddie in Chapter 5; Basket Ball Court

Hospital

Matt in Chapter 2; South Side Park
Freddie in Chapter 2; Railroad Yard or Chapter 3; Station Zone at basketball court
Tim in Chapter 3; Railroad Yard

Clinic

Patrick in Chapter 2; Hospital Zone or Chapter 3; Shopping District
Mike in Chapter 3; Station Zone in front of Las Sombras Cantina
Freddie in Chapter 3; Abandon Subway

Killer Gear

Frank in Chapter 2; Downtown Street
Penn in Chapter 3; Harbor Gate (pay $500)
Hyde in Chapter 3; Downtown Street (pay $500)
Rodney in Chapter 3; Shopping District
Hazard in Chapter 4; Gas Station
Guyina Suit in Chapter 5; Harbor Gate
Penn in Chapter 5; Abandon Subway

Dick's Barbershop

Cobb in Chapter 3; Gas Station
Cobb in Chapter 5; Southside Park
Surfer in Chapter 5; Southside Park
Cobb in Chapter 5; Railway
Nigel in Chapter 3; Station Zone under stairs leading to rooftop