My first thought when I read this was possibly a mild case of hyperesthesia syndrome?
The spazzy behavior fits. It doesn't always present with the classic "rolling skin" or tail biting. Not at all common to see it in a kitten though. And I've not seen or heard of panting being a symptom. But it's a weird condition so who knows.
What breed is your kitten? Oriental breeds (Siamese, Himalayan, et.) are prone to this. I'd be seeing the vet about the panting for sure.
The leg biting is just a cat thing, particularly with kittens. My two chew on each other's ankles all the time. It usually results in the "bitten" giving the "biter" a bit of a smack down then they go back to pretending to ignore each other. Try redirecting the baby with a toy, feather on a stick, anything to get his attention.
Many have forgotten this truth, but you must not forget it.
You remain responsible, forever, for what you have tamed.
~Corkie - Tuxedo, at the bridge (probably hogging the sunbeam)
~Sparks - Calico, 15 yrs
~Jollip - Senegal Parrot, 13 yrs
~Yeti - Himalayan, 12 yrs
~Pepin - Silver Martin/Dwarf Rabbit, 8 yrs