The first time I cooked Xmas dinner, I cooked for 12 adults and 2 children!
Dd2 was only 10 weeks old and still BFing!! Dd1 was just 5!!
It went surprisingly ok, I did a turkey crown, gammon joint, beef joint and a three bird roast, then roast tatos (goose fat) mash, carrots, parsnips, peas, Brussels, yorkies, pigs in blankets and braised red cabbage.
I also did a nut roast for vegetarian (except chicken and fish) SIL
Timing was key. I prepped as much as I could the night before, and DHs job was to keep everyone out of my bloody kitchen and their glasses sufficiently topped up!!
I did homemade celery soup and croutons to start which was a hit, and I made sure that the dishwasher was on a quick cycle and was emptied immediately so I could refill it and not end up with mounds of crockery everywhere!
For serving, I got everything in to serving bowls, meat platters etc and then served it all carvery style IYKWIM.
Desert was cheesecake, Xmas pud or trifle, followed by coffee, mince pies and cream and after eights.
I was amazed I did it to be honest!!! Nobody died either
As for tables, I have two ikea jokkmokk tables - both four seater. I have them together in a long row as an eight seater, or together in a square as a six seater. Cheap and cheerful at £90 each for table and four chairs!
Oh can I also mention, it's my birthday on Xmas day too Never quite sure how I got that gig!!!!
Cook and slice meat the day before, just bring out beforehand to get the chill off. Stuffing balls and pigs in blankets made the day before, placed on trays, covered and popped in the fridge. Veg all prepped the day before. If you have a big enough steamer this will free up loads of room. I would go for soup as a starter as it will be easy to prepare in advance and heat up quickly. Pudding is down to your own personal taste really. I would buy ready made custard and ice cream. For ease also buy a frozen dessert that can be served cold such as a pavlova (just remember to take it out in time!) Christmas pudding takes a few minutes in the microwave. All food set out in dishes for people to help themselves with gravy in a big pan with a ladle. It's not exactly elegant but ensures you have a fighting chance of having hot food Above all relax and accept any (useful) help and alcohol you are given. In all honesty if you have your timings vaguely close it is one of the easiest meals to prepare for a big number