I hate flyrants so much, but I could probably have a fun time against someone using only 2 if they are your only fliers and the rest of the list is questionably useful. (3 is where I draw the line)
I'd say just use Malanthropes to beef up the list. They are arguably one of the best units in the game right now if only because they just go "screw you" to gunlines.(especially when combined with super fast hormagaunts). The rest of your list will be much more powerful instead of just sitting around waiting for the flyrants to carry the game.