RE: Factory Loads or handloads for kids H&R?
Unless you're really just looking for a project to work on, I'd stick with factory or "factory" reloads in the 150 gr. range. I don't think 18 inches or so of barrel will give you much difference in performance, and you're not shooting really long distance. I'd gladly trade a little velocity for retained energy at distance too, with hogs especially.
I could be wrong though. Nothing wrong with trying. More loads means more excuses to practice too.