I have no clue where you got that "rule" but as previously stated, it's way off. As for the aggressiveness of the fish because of cramped conditions is more of a longshot than judging each individual fish for their particular demeanor, although no two are ever alike. IMO
you're about 45g shy for a copperband and another 15g shy for the kole. I see no problem with any wrasse selection but with any fish you're going to need to be selective if you want any kind of reef.
Sent from my iPhone that doesn't like me. Or you.