So Sam had an awesome idea for the front door which I'm very excited about, partly because it also solves the problem of what costume to do. She suggested that I have the front door open, and set up a backdrop a few feet behind with a painting/drawing of a landscape, or villa, then dress up like the Fat Lady/Gryffindor entrance. I'll also put a wood 'frame' of shelf paper, or faux wood paper around the edges of the screen door. I'm also hoping to take the screen part of the screen door out, further making it look like a painting.
The difficulties will mostly be with creating the backdrop. Talked it over with Sarah, and of our several options (paper, kinkos, drawing), the 3rd option will probably be the cheapest, if most time consuming. But I can get a canvas drop cloth for pretty cheap, and I think if the scene is pretty basic, I can do stucco/bricks pretty easily. We'll see.
I'd also like to get some gold chocolate coins and hand those out...from Gringott's Bank:)