Elegant but substantial Party Appetizers and Finger-food

It's my best friends major birthday coming up in December and I'm going to have a surprise party for her. It's probably going to be around 60-70 people and it's good that it's in December as I can disguise it as a Christmas party.

You would have to see us in action to understand the wackiness that goes on between us two. We've held an elaborate Dog Wedding, set an entire dinner party around a "rubber hand" that was the honored guest and in general have just had the best times. She had a party for my B-day a couple of years ago that was just incredible and even located my long-lost childhood friend who flew down from Canada, that I hadn't seen in many years. So this has to be special.

She's been singing in clubs and with local production groups for the last few years and this is what she really enjoys.

And because of this, I thought I would try to give this party something like a fun "Grammy theme". Maybe have her picked up in a limo and roll a red carpet out on my driveway. Have all the guests acting as "Papparazi" ? Some celebrity impersonators? Some Glitz?

Now my dilemna is food...

I want to have a lot of food, but nothing that people have to sit down with a big plate, knife and fork, that's messy to eat. Still want them to be full though. In the past I've done the thing where I've rented tables/chairs and just don't want to do it...People seem to have a better time, moving around and I have a lot of places for people to sit. I've got a large outside area, but sometimes December can be miserable.

I'll probably cook a few large beef tenderloins, shrimp...????

The recipes I've seen on this site have been amazing so any ideas would be greatly appreciated. And of course, anything I could cook in advance and freeze would be a God-send!

Thanks
Kat