If Kelly does go out of her way to selectively attack The Donald, FNC may find that it won the battle, but lost the war if Kelly can be called out for any inappropriate antics that might generate a blow-back.
OTOH, at least people watch RNC debates.
Fox isn’t aware of the blow back from August went a bunch of people (I don’t have a figure but I’d say AT LEAST tens of thousands) aren’t watching FOX now because of her nasty liberal tactics. If that’s not a blowback then Fox is stupid to even attempt this.