I’ve written this assuming you will be doing most of the cooking but switch around if needed.
Put the drinks in a visible location e.g on the counter but not in your prep space for food or where people will be in your way. If there isn’t space in your kitchen without everyone getting in your way, then set up the drink station in another room. Put glasses there too, tell people to help themselves to drinks. Same with nibbles. It’s DH’s job to then keep this topped up and make sure that everyone is staying away from the cooking area.
Do some of the prep a few days before or the day before. So you could make Yorkshire puddings (I know they’re a contentious issue on MN but we love a Yorkshire pudding with Christmas dinner) a few days in advance and freeze them. Prep your vegetables the day before. Don’t push yourself to make everything from scratch. Especially things like pigs in blankets, nobody is going to notice the difference if you roll those little piggies or not. Especially at Christmas you can buy some really nice gravy that isn’t bisto, so don’t feel you need to make gravy from the meat juices (even if this is something you would do normally).
Write down/type (and print off) your instructions. So you want to write down timings, working backwards from when you want to eat. Write down everything, putting the oven on to preheat, turning the oven temperature up or down, boiling the kettle. If you are making something from scratch or tweaking a brand version to how your family like it (we cook paxo stuffing differently to how the pack says) write all those down with the instructions for example 11.15 - melt 50g of butter for stuffing, then add one finely chopped medium onion, boil kettle 11.20 - make stuffing according to instructions, stir and add in extra onion. Then put the instructions next to the oven with a pen, crossing out each instruction as you complete it. That way if you get caught up in something, someone else can just pick up your instructions and continue cooking. It also means that if something crops up (someone broke down outside our house last year just as I was about to start cooking), you can just adjust your whole timings without getting stressed out trying to work it out all over again.
Depending on how helpful other people actually are and your kitchen layout, you can either set other people tasks such as setting the table or chopping veg. My task growing up was decorating the trifle and I’d be shoved to one end of the kitchen with the trifle and my decorating items (an orange, a flake, hundreds and thousands, maybe some glacé cherries). Get DP to wash up/load the dishwasher as you go. Without getting in your way, so they might need to wait for a few minutes while you complete an action to grab the pan or they might need to take the pan from a different angle. Set up a system beforehand though - so anything on the left side of the oven can be washed but anything on the right side is still in use. If they are putting away the clean pots, wait until you’ve got a bit of a break until the next cooking activity.
If you forget something, you leave the pigs in blankets in the fridge or forget to do the sprouts, don’t force yourself into a panic trying to cram them in. You’ll just get yourself stressed and it’s not the end of the world. If anyone says anything, roll your eyes and drink more wine.