craftgrrl | craft help for party

I posted earlier about face makeup for my classes opera. We're having a family cast party (and masquerade ball for the children after the show. My boss has agreed to order dinner - pasta and garlic bread, but that's it. No dessert or hors d'oeuvres. But this is the first time I'll have met half of the parents, plus the program auditors will be there. I really want to make a good impression and surprise the kids. I'm turning the cafeteria into a winter wonderland (hopefully). I bought white table cloths and white lights. I saw this craft that uses fishing line and cotton balls to look like falling snow from the ceiling. (And, I'm attempting to make a large stuffed snowman.) I also have white streamers. One wall is going to be covered in a white sheet where the parents and staff can write congratulations notes with sharpies. The kids will also autograph it, and will hang it in my classroom when the party is over. There will also be black and white photographs of each child. I also need centerpieces (preferably white or silver). I bought tinsel-if that helps...

I wanted to have the kids do their handprints/footprints and signatures like Grauman's Chinese theater pavements. I looked at plaster of paris, but its pretty expensive for what I need. Is there a kid friendly cement/plaster mix that I can make from home made ingredients?

I'm also making VIP bags for the cast. I'm putting a copy of the book the opera is based on, and some original music from the show. Any cheap but nice suggestions to jazz up the gifts in the bag?

Suggestions for centerpieces?
And suggestions for that theater pavement?
And suggestions for the VIP gift bags?

All of these items will be gifts for the children and their families.