whatever. I think this is being WAY overthought. If they want to come, let them come.
I guess the ONLY thing I would put as a caveat is this: that they ask ANYONE if it's ok to film them and their stuff before doing so.
Frankly, I don't think there's going to be much at the party for them to see. There's going to be far more replicas than screen used pieces, and usually these are more about the meeting up than the showing off.
I think getting an room of their own is a rediculous idea, as they'll be lucky to have two or three screen used pieces at the entire party. But hey, theyr'e free to spend their money however they want.
In general, I think it's a bad idea to turn people away from a prop party because they don't celebrate their passion for the hobby in the exact same way that you do.
And here's another great idea: why not ask them to bring some of THEIR screen used props for US to see??