your stirrups look a little too long.
your legs look fine, you're just do way too much work.
sit, and wait for your horse to lift you out of the saddle. The purpose of a jumping position is to balance ourselves over our horse. If you took your horse out from underneath of you... you would land flat on your face, if that makes sense? Your hip/upper body is way forward. Ideally, your tush should just hover right over the center of the saddle. You aren't closing the hip angle, your horse is.
Your release is nice. Yes, your heels do need to come down.. and I think shortening your stirrups will help.
I would suggest doing two point and a stand for starters. Put your hands straight out like an airplane. Twist your body right and left. Put your hands up in the air. Once you can do that with your seat/legs staying perfectly still in that two-point position, you know you're stable enough to try it at the walk.
What might help, if your horse is honest enough... to close your eyes while approaching a jump and just feel your horses movement.
Anyways, I'm not very good at critiquing, I'm sure somebody else will give you a very adequate response!