Is there a quick and easy way to make holes dependent between parts. I have tried to copy and past which works decent if the parts have similar geometry but as soon as I try to edit the holes Creo crashes with a fatal error. Is there another way that works to make the holes dependent without putting the holes in the assembly itself?
You can make relations between parts to make them alike.
This makes the assembly dependent.
You can also make one or both holes in an assembly cut.
All depends on how quick and dirty you want.
Yes and no. Are you talking about standard holes (taps, counter bores, etc.)? Do you want them to simply stay in alignment or stay the exact same size? (When one changes size the other one does to.)
Probably more than you want to read, but take a look at these discussions:
I'd look at using a skeleton to define the hole locations, perhaps with datum points in a sketch, and pass those locations to each part.