In your shoes I would stick to my favored rifle and made sure I have everything to keep it happy during the trip.
Unless of course, it is part of the trip memorabilia

When I fly, I make up two batches of ammo and put them in seperate bags. A sort of fail-safe thing but I've never lost either. knock on wood.
I've never thought of a small kit with repair parts for a rifle although I think it's a grand idea. I do carry a sighted-in back up scope in QC mounts for my principle rifle.