Individual Frittatas

In the past, I've made sweet potato gruyere, broccoli and leek, and classic spinach mini frittatas. I make them in advance, fill mini muffin tins, freeze them unbaked, then pop them out and store in a freezer bag. I've done it up to 2 weeks in advance. The day of, I put them back in the tins frozen, sprinkle with cheese, and bake as needed for the party. The bonus is that anyone helping you in the kitchen can manage these as well.

These Salvadoran breakfast cakes are delicious and a nice change from muffins.
http://food52.com/recipes/12535-salvadoran-breakfast-cake-a-k-a-quesadillas

Agree with SKK with reheating frtittatas.

Are you locked into an egg dish? If not, you have options.
Not a fan of kale, but SKK's recipe would work with spinach or swiss chard, if you are so inclined.

Polenta (made ahead, cooled, cut into blocks, re-warmed stove top in olive oil), sauced with warm mushroom ragu (also stove top reheated).

Yogurt and granola parfait bar. Granola made ahead, fresh fruit dice. Not a meal but something to consider as a small non-cook side dish that guests could make to keep occupied, small bowls or flutes.

Have found that reheating individual frittatas makes them very tough. My go to recipe for the situation you are in is Quinoa and Kale Crustless Quiche. It is wonderful at room temperature. http://food52.com/recipes/14244-quinoa-and-kale-crustless-quiche