As far as your first question goes, your endurance wasn't regenerating to 64 because you only had 30 health, so yes, it was working correctly. You lose as much health as you do endurance while in combat. After combat, you will regenerate your full endurance pool assuming your health pool is larger than your endurance pool.
2nd: There is a utility talent called Field Triage that can refill a portion of your health once per rest. Other than that, no.
3rd: Don't know but assume yes.
4th: No idea.