Have em hold up a LA and a SA offhand
I toted a 30-06 for a while and I'm 5' 6", I got tired of shouldering and having front hand land on the mag box instead of in the forearm checkering
It was a real problem for me
(Also the longer rifle for shorter people gets the muzzle too close to the ground which aint good in snow, or rough terrain)
It could elimate the possibility of rifle not fitting them, would not be cool if they found after a day in the field the rifle was too big for them.
I think a standard length action is for guys/gals > 5'8"
SA for the smaller people, or people who put big miles on
No matter what you end up with. Congrats on being able to do this for your kids and I hope it works out for you and you guys make some memories.