Re clear up - assuming you have a dishwasher, set it going immediately after breakfast and make sure it’s emptied ASAP. Then all cooking pans etc go into it as they are finished with, set it going before you sit down for lunch. Depending on the length of the cycle you can either take ten minutes between courses to empty (and put away!) and reload, or leave it until you’ve finished.
Meanwhile, as you clear the table have a system - something to scrape food waste into, a bag for cracker detritus, and then stack plates etc. into plastic crates. Depending on space you can then dump the crates into the utility room if you have one, a corner of the kitchen, or just outside the back door. And then keep on emptying and reloading the dishwasher at intervals.
If you are hosting multiple meals over several days you might find it simpler to store the clean plates and cutlery on the table rather than scrabbling around at the back of cupboards (this assumes that like me you don’t have cupboard space for 12 place settings and so tend to store the excess somewhere inaccessible).
Personally I quite enjoy the chance to escape into the kitchen periodically to do a spot more clearing in peace and quiet (and to snaffle cold pigs in blankets) but appreciate that’s not everyone’s cup of tea. Depending on who is staying we also sometimes just end up with a crowd of us in the kitchen, one washing, 2-3 drying and putting away, leaving roasting dishes in soak for the next day. Anyone not doing that gets the joy of helping small children put together fiddly Christmas presents!
Another thing to think about if you’re catering for much larger numbers than normal - consider where you will store the extra food. If your fridge is usually full anyway, it might be worth digging out some cool boxes or clearing space in the garage for extra veg and other things which you normally keep in the ‘fridge but which are giving way to meat and milk for the masses.
If they’re staying a few days it can be useful to keep an eye on milk etc. and plan to send minions (or escape yourself) to the corner shop periodically, rather than trying to keep enough for the whole holiday.