Other then the safety cut, magazine release side button cut (for later ones), and the bolt handle cut, are there any more difference. Can a Mark X action drop into a 98 Mauser stock with only minimal fitting?

I use the same pattern for both.

I swap both between stocks. Just not the 98 4 screw guard.

Yes, they are the same.

Carefull there the barrel channel can be different. The action in some cases has required some work, normally not a drop in, but then to me there is no such animal as drop in.