Prep veg the day before, peeling and chopping and leaving in water (spuds, carrots, sprouts). Onions and parsnips go in airtight containers with no water.
Take the onion and carrot peelings (if clean) and throw into a pot with the turkey giblets and any herb stalks you have, cover with water and let slowly simmer to make your turkey stock for gravy. You can even mostly make the gravy (tou’ll Probably need to open a bottle of wine for a glug into it, so chef usually needs to test that!😉) on 24th, just leave it a bit thick to add the turkey juices from roasting tin.
Think about both cooking pots/trays and serving dishes - do you need any to do 2/3 things and get washed in between, do you have enough salt and peppers, milk jugs, gravy boats etc for the table? Do you have a a large teapot and coffee pot for later? What can you borrow to supplement your own, or what do you need to buy (whether disposable for 1 use or that you will use again so more substantial).
Where possible, I would make things that need to be different (gf stuffing) the same for everyone. Perhaps have seperate gf crackers for cheese but plenty so everyone can have some (M&S do lentil based crackers that are nice).
Work out what time you want to eat at, and work backwards from there for your timetable. Cover turkey with foil and a bath towel folded over it when it comes out - to rest for at least an hour, stays hot up to 2. That gives you time to turn oven up high and cook potatoes, roasted veg etc.
Make sure you have at least 1 roasted per person, but if oven space is an issue, think about what can cook on the hob - so maybe a bowl of mashed potatoes to supplement the roasties, steamed broccoli or sprouts, steamed cauliflower with a cheese sauce just pooped under the grill to brown for a couple of minutes at the end...
Frozen petite pois peas can be put into a pot or heatproof bowl in the morning to defrost and just need a kettle of boiling water to cookt them enough as you clear the starters dishes.
Baby leaf spinach in a colander with a full kettle of boiling water poured through it is enough to cook that (I usually use a clean serving spoon/masher to squish out any excess water before actually serving it), also a last minute as you serve item.
Starter should either be cold (prawn cocktail, smoked salmon, pate etc) or simple to cook/reheat (soup, tray of stuff to literally just pop into oven with no prep ont he morning).
Dessert should go in oven/steamer as you sit but be pre-prepared. Pudding, a crumble, sticky toffee pudding...
Or else cold - pavlova (last minute throw cream and already prepped fruit and crushed flake over it), fruit salad, cheesecake, chocolate tart, lemon tart....(jelly and ice cream?). Don’t go overboard - max of 3 types no matter how big the numbers. Expand the quantities not the variety.
Have a bowl of cream whipped for the table as someone will always want it over their dessert. (Or is that just our house?).
Hand out jobs if you can but be specific - both in advance and on the day. Take control of the kitchen, only allow those in who will actually help and not get in the way, or someone who will sit with a glass of wine and chat to keep you company (and not get in your way).
Put the drinks somewhere else - dining room on the side, sitting room, out of the way in the kitchen - but not in the areas you will be working. Glasses, slices of lemon/lime/orange (if you want those - and chop into airtight container on 24thbif you do), ice in a bowl etc should all be in that area too, before visitors arrive.
Try and have a few nibbles , in case timings don’t quite work, so there are not starving horses demanding food when you are flapping.
But you won’t flap!
Relax, work out the timings beforehand, write down the plan so you know what should happen and when, and enjoy!
If it’s not in your way, have someone washing up as you go. But at least have ge sink full of hot sissy water to soak pots and to wash the knife that falls on the floor to reuse it again etc. have tearowels rwadilt accessible for willing helpers.
And once dinner is served, chef is off duty and other do the clearing up!