I would par boil...the shells...then stuff when still rather tough...the sauce and the baking will cook them the rest of the way...and yes..raw eggs to "FIRM" up the cheese.
Usually use 2 eggs per pound of cheese.
Thanks for the verification. I went with basic food principles, and came up with about the same thing. I've already got it assembled, waiting in the fridge for the timing to be right for Trill getting home. I also made polenta, cut it into diamonds, and I'll fry that up at the last minute to serve with the shells.
/john