SallyBR, what a golden opportunity to show off yr superb cooking talents. I cook & freeze my
mom's REC for buttermilk pancakes (posted fairly recently up above) all the time so as to avoid having any leftover batter go bad on me. I would surely think your little appetizer pancakes could be cooked & frozen ahead.
Another great REC I've used quite successfully is charlie's Hot Brie Kisses. I assemble and freeze them in mini-muffin pans and just pull the pans from the freezer to bake. Have always gotten rave reviews on those. I use green, red & yellow hot pepper jellies which make a colorful mixture on my serving trays. For garnish I have used combinations of colored bell pepper tops (red, orange, yellow, green) which also serve to make that appetizer item really pop and catch guests' eyes. Follow the hints listed on charlie's REC in T&T--the one about pulsing the brie in a FP B4 using--rind & all--is worth its weight in gold.
A suggestion for beverages--when I work out of a private home, I ice down the washing machine and stash soft drinks & beer in it. That way I don't have to lug so many ice chests when catering, and the ice in the washer melts so at the end of the party, I can spin the tub to drain out the water.
With 50 to 60 guests expected, I trust you have a friend or two to help as servers. If not, I would definitely hire at least one waiter/waitress to perform that duty, or you won't get to visit with your guests very much. I have a timer that I clip to my apron so I can keep tabs on items baking in the oven while I am out amongst the crowds passing food & refilling wine glasses.
You can pull all the platters & bowls ahead that you want to use to serve from. I typically put post-it notes on which plate will have which appetizer on or in it, and I also put notes on the table where each item is to sit so I get the best blend of colors. Anything I can think through & do ahead is done ahead--my garnish is all thought out ahead of time, too. I spend a ton of time on written planning so there will only be minimal thinking to do at the zero hour, and I can deal better with any last-minute snafus.
We are all out here rooting for you! I'm positive things will go swimmingly. Best of luck!
http://www.eat.at/swap/forum2/104_Hot_Brie_Kisses