Thanks for the fast replies, everyone. You guys are a huge help.
I managed to seat the shepard's crook, and after dry-fire, the pins are now seating fine.
Today, I may run to the hardware store and see if I can't find a longer screw to put thru the back of the receiver / trigger guard into the grip, so that its held in place by two screws instead of one. Maybe it will pull the grip flush after I do that.