Thompson Center made a Cherokee and Seneca rifle. Near identical guns with slightly different trim package. The caliber wre 32,36 and 45. The lightest gun (and most popular and most versatile) was the 45. That was due to keeping the barrel OD the same and boring larger hole. It has a short light barrel and a slender stock. it might come in right around 5 lbs, maybe 6ish max.
This model will carry a small premium (around $500 maybe a tad more) , but; the easy resale is there. It is a very easy resale, unlike some custom gun that requires customer education. They are plenty light for a youth to handle and yet not so small that it cannot be used into adulthood. You would have no problem from recoil with a light load and 45 round ball.