TC Venture compact, with adjustable length of pull.
Are the 700's full size actions in youth stocks?
I would try to find a older 700 (1990's ish and older) in .243 and just find a youth sized synthetic stock for right now. Kids being kids, nice wood stocks will get dinged up and scratched. Then when they reach the age of appreciating what they have, put the wood stock back on.
Savage Axis and a $99.00 stock. Can't beat them for accuracy even at 3 times the price. We have 3 people now that shoot F Class out 1000 yards with savage axis. The stocks are cheap-Yes,but that only matters if you put a bi-pod on them. Holding them in your hand or off a rest the stock plays no part.