One thing I would put at the top of your list is a suppressor, I put a brake on my kids 260 and he hated the noise of that more than the recoil, took it off and he could only shoot a few times before it was thumping him too hard but he enjoyed it more, got a suppressor and between the recoil and noise reduction. Both boys will shoot it all day long.
I’m a big tikka fan, I’ve put all of mine in chassis’s for the kids, everyone is looking for a shorter LOP for their kids and I feel they often over look the cheek rest, hard to see through a scope if their head is free floating above the stock.
I don’t own one and have only shot one once but maybe a sig cross or something along those lines would be a good option, easy to adjust LOP and adjust the cheek rest to get a good picture through the scope.
Most my kids guns have 3-15 power scopes, wide FOV and good eye relief is key things I’d be looking for. It helped them acquire animals quicker when they where starting out.
Top pic is my 12 year old (Green ear pro) shooting a tikka with a 2-10x42 nxs, you can see his face is floating above the stock to look through the scope. Lower pic you can see he has good contact on the cheek piece, when that cheek riser is setup for my kids I can’t get low enough to look through the scope. That scope is a 5.5-22x56 nxs. That would really never work for him without a cheek riser for them. When his arms where shorter I’d take that folding adapter out to shorten the LOP for him.
Same factory tikka my 10 year old (blue ear pro) you can really see the difference on him between that and another chassis. That tikka is a full length buttstock. Chassis is adjusted down for him.
Another thing to note is the grip angle between the 2 stocks. Factory stock he’s stretching his finger out to get on the trigger, vertical grip on the chassis gets them closer and gives them a little better trigger control
