Ron is there. Obviously. And he'll probably look a little too excited to fight when things go south. If he sees Fred as a shadow, his fighting will get a little more frantic but cruel. The Dark Wizards picked the wrong face.
Tony will take Morgan because it sounds like it will be a delightful way to spend a day she should have been having with her mom dying eggs from the chicken coop back home. At the first sign of trouble, he'll make eyes with the first Avenger he sees to know that they've got it covered before he hauls ass out of there to keep Morgan safe.
Eleven is there. He loves a party. Is probably wearing a tux. He won't do any of the fighting, but will be trying to get people to safety.