I hope you have a wonderful Christmas morning, with your lovely family.
Another vote here, for reminding MIL that of she wanted to see the DGC opening their other presents, then she really should make the effort to get there early.
Our morning is different again, as we have always had family staying/visiting from a distance, so in a hotel). The DC will have their Santa present, and usually a present from us (or a small stocking). Then, everyone arrives about 10ish, and we do presents from GPs, aunts, uncles and cousins.
Boxing Day, we do a couple more presents from us, and then each day after they will have a few more presents.
I've never before though about how strange that is, it's just something we've fallen into. Mainly because PIL harp on about how much they get, or DP get them lots, so it would take all day to sit down and open.
Hey ho, nowt as strange as family!
Have a wonderful time, and Merry Christmas!