Sounds very difficult and at any time, Christmas or not, go for preprepared food, I started doing this when I realised no one was helping me at all, and I decided one year frozen roast spuds, sprouts everything, and no one noticed, if anyone had complained the answer would have been, OK no problem, you want fresh sprouts or whatever, that's your job to prepare them. I've never looked back. Also one year when the children were younger I ended up in a and e on Christmas eve, and couldn't do the things that I thought everyone would miss, but guess what they didn't so that was that
With regard to going through your things, I think unless you locknstuff away the only thing to do is set some boundaries beforehand. I always liked seeing all the different things at elderly friends and relatives houses, so it would be a shame if you had to completely hide everything away as well as a huge pain in the bum,, while it might be necessary as an emergency measure although you could hide the power cord , much better to tell mum and the children at a calm time when you're not frazzled that there are boundaries, if they want to learn how to use the sewing machine that's OK, you will show them one at a a time how to use it properly, no mucking around,, or how to use the tools. They are not toys, and visiting friends they would not be allowed to do that at a friend's house. A break sounds a good idea if you can manage it telling family that you are going to do it early in the year.