Clear call yes. You don't want anyone folding when all you have is a nut flush draw. The more people in the pot, the greater your equity. So don't shove, instead call and hope for an overcall on the flop.
However in this case you would be closing the action on the flop, so if the hand is still 3 ways, yes you shove the flop. It doesn't really matter what you do heads up, you can't fold, so shove or call flop call turn, either is good.
Preflop I don't like playing A578 if I know someone has AA. One of my cards is dead and 578 just isn't that great, which leaves the nut flush draw. Usually when you get a flush draw, you won't have anything to go with it, which means you will be 40/60 dog on the flop.
Lots of reverse implied odds with your hand, I think a fold to the 3 bet is correct, even in position because the Stack to Pot ratio will be a lot lower and you wont hit enough on the flop.