I just prebaked them, and then filled the cups; didn't bake the cheese mixture at all, since I figured it wouldn't stay warm outside very long anyway!
The block party, by the way, was great! About 14 of the neighbors came, and it was wonderful to meet folks we'd just waved to in passing; gave a chance to meet new friends, and exchange ideas.
We're going to do one in the summer - a grill off for all the guys! There's a little cul-de-sac with only 3 houses on it, and one of the folks there has a brother who's a policeman, so we can block off the cul-de-sac, line up the grills and have at it! Should be fun!