RE: Heater in a ground blind?
When I was young and on my first hunt with my grandfather we hunted a old abandoned house on a lease. Though we were sheltered (somewhat) we still got cold. He told me to wear layers, that it would be cold, and when ever I was ready to go in we would go. He didn't force me stay out and be miserable. He slowly introduced me to what I would eventually be accustomed to. I thought this was great.
A few days later my uncle took me out. He showed me the latter stand I was to sit in then went on his way. His last words was "don't get down or leave until I come back." I froze my butt off and it was the most unbarable, horrible hunt. I still have those cold as you know what moments. But, now I know my limits.
I'm sure your daughter will have a great time, but as my grandfather would say "don't make her fish if the fish ain't bitin'." In other words when she stops enjoying it, stop hunting.