I'm using craft foam for the rest of the armour, so I do want to stay with using craft foam. :3
My only concern, however, is how would I be able to apply the foam to the the hat to make it look... Er, natural, so to say? Also how to hide the physical hat, if you know what I mean.
As long as the craft foam is used to keep it uniform with the rest of the cosplay, then I've got no complaints, lol!~