Ahmey's more the type that remain friends with because you never feel the urge to take it any further.
Fatina's too clingy to fuck and let go. She'd BAAAAWWWW and make you feel terrible for it and not even mean to.
Kaaya seems like the sort that sleeps around, but would also make for a good housewife if you wanted to settle down with her. The circumstances that she's in right now are probably a bit extreme.