We don’t do 1 Dec or Christmas Eve boxs. Also stocking are generally chocolate or what fits in there we’ve never made a big deal out of the stocking, in fact I wish I hadn’t started it.
Christmas PJs I try and get 2 years out of them then they are worn year round. They are given on 1 Dec with advent calendar. we’ve never had fully matching family ones just matching kids.
General pjs I usually buy last minute in any sales, these I use to fill out the pile.
Advent calander a choc one each. We introduced toy ones, again slight regret as we are now stuck doing 2 each which isn’t cheap.
My focus is the “must have” their main Christmas wish lists. Once these are done I’m safe to buy extras.
We don’t do set amounts, rather equal quantity, over time the amount spent tends to even up.
You haven’t said genders so here is a generic to do/buy list
4 Santa presents - 4 is an arbitrary number I picked years ago.
4 parent presents
stocking fillers - colouring books, crayons, pencils, hair brushes, hair accessories, selection box or tubes of sweets a novelty toy.
Extra bulk out gifts - PJs dressing gowns, oodies, cushions/pillows
At this age I would have manipulated the must have gifts to suit what eve I’d already bought in sales throughout the year.
id also try thinking ahead, use post Christmas sales for Christmas themed stuff, pjs, bedding, crackers decorations etc.. We have all new Christmas bedding this year, I bought each set for £1 off a clearance shelf in the range just before Easter.