I could possibly be speaking out of turn because I don't have a son, but I would treat circumcision like I would a body modification (i.e. body/facial piercing, tattoos) and not allow it until he turns 18. At that point, he'd be an adult and could choose to do whatever he wants to his body (although I would certainly hope he chooses to stay intact).
I LOVE your DH's reaction. Very levelheaded and got the point across VERY well :)
As far as breastfeeding your toddler, you keep doing what you're doing for as long as you (and your child) want to keep doing it! Who knows, maybe you'll inspire some other new mother to join you ahead of the curve!
I wonder if maybe your son is picking up on the tension you're feeling and that keeps him up?
Maybe you could try easing into bedtime. Maybe a bath, a small snack or nurse, bedtime story, lowering the lights. That way he would know exactly what to expect and maybe he'll be more open to sleep.