A pound of fat burns ~3 calories, while muscle is ~8 per day. Sure, it is different, but unless you are the Rock, most people do not have enough muscle mass to make a difference.

This is just not true, if you look at women and men of similar height men still burn significantly more calories.

Hormones, I'm sure, play a role too but testosterone is sticky. More weightlifitng raises your testosterone - so you should be seeing that benefit.