Yeah it's like they saw the success of the AR platform and tried to figure out how to apply it to products they already had in production. The adjustability of the AR style stock does make it handy for growing youth, but the point was missed that ARs are often pretty light. Like you mentioned, by the time that 7.5 lb Mini is scoped you're looking at a 9 lb+ setup, which isn't particularly kid friendly.
It's almost like the people making these decisions at Legacy Sports/Howa don't quite understand American culture. "All your base are belong to us."