You are either jumping ahead or getting left behind, in all the pictures. Really practice your 2-point, at the walk trot and canter, this will help you get a better feel for your horse. Also you aren't giving enough. Resting your knuckles on the horse's neck isnt a bad thing, and you should do it, especially since you are losing your balance and having trouble staying with the horse. Try grabbing some mane, that is a lot better than using the reins as balance. It looks like you are just planting your hands down and not moving them with the horse at all. Practice moving your arms with the horses mouth, if you do that your horse will round more over the jump, and not be so flat like on jump #8.
Also practicing your 2-point, and without stirrups will help with your lower leg from slipping back..try raising your stirrups a half a hole, it may also help with your leg position.