Seriously don't stress. I have hosted way more people with one oven. You will be fine. People eat when they eat!
I don't bother with starters. There is enough food as it is.
I find the prep is the thing that takes an age so I do as much of that as possible during the days in the lead up to Christmas day.
I have already diced my onions, bacon and apple all in freezer to throw straight into the pan for the shredded sprouts.
I made the stuffing today; in enamel dishes now in the freezer to put straight into oven on Christmas day after the turkey. These will go straight to the table from oven.
My BIL will make his lovely red cabbage and bring it with him on the day.
I will peel, parboil and coat the roast potatoes in goose fat/rosemary/garlic on Christmas eve. They will be on the oven trays once cooled I will put them in the fridge. They will come out on Christmas morning and sit on the side ready to go into oven after all the meats.
Carrots/parsnips - cut into chunks - in pot with orange juice/thyme/butter/red wine vinegar(jamie oliver recipe). This prep can be done the day before. On Christmas day, i just put them on the hob and let them do their thing Christmas day. I would have liked them honey roasted but trying to free up the oven so this will do. As the water in the pot boils off the orange caramelises.
I will prepare the bread and butter pudding on Christmas eve. I will have it in the fridge and then put it in the oven as we eat our Christmas main. The only task I have given my brother to do. The family will bring the other desserts and drinks.
Dh will do all the cleaning and tidying of the house ready to receive guests.