Based on speculation and sources, here's a VERY unlikely but first draft cast:
Guys:
Dan Gheesling (BB10 Winner, BB14)
Frankie Grande (BB16)
Derrick Levasseur (BB16 Winner)
Paul Abrahamian (BB18, BB19)
Swaggy C Williams (BB20)
Josh Martinez (BB19 Winner)
David Alexander (BB21)
Tyler Crispen (BB20)
Girls:
Nicole Anthony (BB21)
Nicole Franzel (BB16, BB18 Winner, The Amazing Race)
Liz Nolan (BB17)
Da'Vonne Rogers (BB17, BB18)
Angela Rummans (BB20)
Bayleigh Dalton (BB20)
Kemi Fakunle (BB21)
Janelle Pierzina (BB6, BB8, BB14, The Amazing Race)