I promised myself...
Don't go for Christmas...seriously. If your parents do not "believe" in AD, then the whole visit will be you trying to prevent further damage they will do and since you'll be out of your home element, the kids will take advantage of that and others around them to manipulate and charm.
There...said it...
Annie movie - I haven't even let my dd watch this one yet because I just know she'll have some issues with it. I think on this one, all you can really do is listen to your gut and go with that. Unless you feel that they would see you and dh similar to the Daddy Warbucks character (permanency/family etc.) and it might "cement" things for them, go with your gut on this one.