Duster 15 Degree Youth Sleeping Bag

I’ll put in another vote for the big Agnes bag with the pad sleeve. My kids used the kid 15 F version with a 3/4 foam pad or self inflating foam pad until they outgrew them. I wouldn’t use an air pad until the kids are a little older unless you enjoy field repairing punctures. Definitely warm to below freezing. I find foam pads to be much warmer for their r value than air pads. This sleep system is heavy compared to quilts. But I can’t imagine trying to keep a young kid under a quilt. My kids would rotate 90 degrees in the night if not restricted by the bag. While my kids sleep system was heavier, their clothing was dramatically lighter so it balanced out. Also, kids don’t go far, so I found UL wasn’t the right approach for kids — we aimed for lightweight by using someUL gear. I can carry a 30-40 lb pack for 3-5 mile hike that a kid is willing to do no problem. As they get older and hike further, they carry more weight and sleep like reasonable people so options expand.

My oldest is 9 and he loves his Enlightened Equipment quilt but I know you said you want to stick with a bag. What we found that worked well was the big Agnes kids bag. They are synthetic but don’t have the insulation in the back of the bag. Instead, it has a sleeve that the slipping pad slides in so the bag/kid won’t slide off the sleeping pad. It is pretty neat.

Might consider cross posting at r/hikingwithkids My kid uses an older big Agnes kids bag that has a sleeve for a standard 3/4 pad. My quilt is lighter than his bag, but his pad is lighter than mine. I like that he can't spin in circles and bump into me at night and he sleeps in it fine. I've been using it for car camping and would consider going for Morrison if I didn't get a great deal of this bag but I really do like that he stays on the pad and doesn't wake me up.

I've used and kinda liked the Big Agnes kids' bags. They've got a pad sleeve, which mostly solves the "kid curled up in the corner of the tent" issue. The ones I bought aren't available anymore, but they were 15F rated and okay down to freezing (maybe lower -- didn't try it). The weight is slightly below 2 pounds, which is in line with the current offerings. That would be heavy for an adult's bag, but my kids tend to carry their own bag, their pad, their own puffy, and that's about it. I usually used CCF with the pads. For colder nights, ALPS makes some super-bulky, very thick CCF that worked well, although it winds up strapped to the top of my pack. I wouldn't trust any of my kids to sleep properly in a quilt. The 14yo, maybe.

I would go with a quilt, they are great for moving around. Zenbivy is most peoples favorite, I really enjoy my Big Agnes.