Disclaimer none of them are bi besides Bale
Bonifer
You found out when you saw him flirting with Jay and sometimes Pete on several occasions, hell he's even asked if he could fuck Jay of course he was joking.
Jay Evans
You found out that Jay was bi when he came out when Grim interviewed him during one of his shoots, hell you wasn't even surprised considering that he always sent other members of the roster pictures of his dick
Jake Cage
You found that Jake was bi during high school when he came up to you and told you that he was bisexual even though he was scared that you would break up with him.
Kurt Bale
You always knew that Kurt was bi but when he came out on Twitter you wasn't surprised at all
Pete Corvus
Pete came out as bisexual by accident when some guy on Twitter kept calling him a homophobe, Pete regreted it later but with your help he embraced it knowing that you were by his side.