easy but nice options would include ready-made croissants or pain au chocolats that you roll out the dough and cook yourself. Could put a filling in croissants if you wanted.
DM used to often do a fry in the oven on Christmas day, while it heated for nibbles for guests and cooking turkey. Just put the sausages and pudding in earlier than rashers as the latter cook quicker. Halved tomatoes are lovely from the oven, and another container with mushrooms and a bit of butter, salt and pepper is delish! Only thing needed on the stove is eggs.
Freshly squeezed orange juice is a great treat on Christmas morning. whether that's from a bottle or done yourself (night before works perfectly).
You could pre-make proper pancake batter and have that in the fridge, to serve with a choice of streaky bacon, maple syrup, berries, nutella etc. We tend to make slightly thicker but smaller sized (fit 3 on a pan) ones for breakfasts in our house (I make batter on Sundays and use through the week to get DD to eat a solid breakfast!).
A more grown up one would be bagels with cream cheese and smoked salmon, or just butter and jam or Nutella for littlies.
One idea I would love to try on Christmas morning is Chelsea buns or raisin Danish. I suspect I could do raisin Danish with puff pastry, raisins and some custard to bind, rolled in a log and sliced. I've seen various versions of Chelsea buns recommended for Christmas - making the batter the night before and forming the buns, letting them rise overnight in the tray, and just baking in the morning.
There's always hot coffee, perfect strength hot tea, orange juice, toast, naice marmalade (bitter with big chunks!), and I often have either fresh berries and natural yoghurt or a fresh fruit salad (breakfast type so not too sweet like a desert) as well. I actually like to have fruit available on Christmas Day as the rest of the food can often be quite heavy when its all added together (both type and quantities)!.