Jan, if you feel that everything is going very well with they way it is, then I would just leave it. You would hate to move the 2 babies and then find out that the mama cat lands up rejecting them.
Trust your judgement Jan, I do.

Can't wait to see PPPIIIICCCCTTTUUURRRREEEEESSSSS!!!!!!! (HINT, HINT.)

Please keep us posted on the situation.

Rest in Peace little one.