I would advise as much make ahead as possible. I make "baked french toast" and don't even call it a casserole! Make the french toast the way you like it and put it in a well buttered dish or baking sheet that is at least 1 inch deep. Dunk the bread on both sides and don't worry if there is egg mixture all over the bottom of the pan, the bread will soak it up overnight. Bake for about 20 minutes and flip the pieces of bread. Place a small piece of butter on each piece of bread and bake again for about 20 min or until browned on top.
Either buy or pre bake some bacon and/or sausage. Just crisp it up and warm up in the morning.
You could also have a make your own breakfast parfait bar. Yogurts, berries, fruits, granols, etc.
If you have a waffle iron, put out the batter and have everyone make their own fresh hot waffle. Maple syrup, fruits, whipped cream etc. on top!
Here's an easy make ahead sweet bread recipe:
Walton Mountain Coffee Cake
1 bag frozen white bread dinner roll dough balls (or 18-20 dough balls)
1 package butterscotch pudding mix
1 cup chopped pecans (optional)
1/2 cup butter
1 cup packed brown sugar
1/4 teaspoon cinnamon
1. Grease a bundt pan (I use an 8 x 8 square pan) and put pecans in the bottom.
2. Put in about 22 of the frozen dough balls.
3. Pour the dry pudding mix over the dough balls.
4. Melt butter, cinnamon, and sugar over medium heat until the mixture is a little carmelized.
5. Pour the mixture over the dough.
6. Cover and let it sit in the refrigerator overnight.
7. Take out in the morning and let dough sit for 30 minutes.
8. Preheat oven to 350 degrees and bake for 20-30 minutes or until the top is slightly brown.
9. Remove from oven and invert on a plate immediately after removing from the oven.