IMHO.....
I'd go with the cut standard stock. Hint: I frequently see take off stocks at gunshows for $15-20 with the butt plate, front bbl band/retainer and tension screw. Your son will grow up in the blink of an eye and the next thing you know you'll want to replace that stock again.
When that happens.....
Put your old stock back on or buy that special stock.
As for the cut stock.....
You could just keep it for your other kids or forward it/sell/whatever to another family with young kids. Or just keep it for your grand kids. Either way......you'll make someone happy and/or it won't be like you're tying up all that much money.
As for the barrel. That's up to your budget. I'd want to keep things light (cheap way: keep factory bbl) as it's suppose to be a "youth trainer." If you want to cut and crown it.....well, it's a small project. But, you'll probably want a front sight. Teach your kid to shoot with iron sights and they'll get the discipline they need for the future.
The trigger pull can be cheaply worked on with the installation of a VQ target hammer kit. IIRC....about $35.
Aloha, Mark