I only watched the first 2 minutes of the first video. The horse seems to be breaking from the canter at the same post each pass. I would work on encouaging the horse to keep moving forward at all times. Even if your horse is cantering, don't take you leg off and just sit there expecting the horse to keep going. Remember if you're not willing to put the work into it, don't expect the horse to either. In other words, if you don't work, they won't work.
On another note, (Keep in mind I ride more centered, not sure how it is in hunters) I would pick your hands up and keep your butt in the saddle more. You seem to be very off balanced in your riding. Also, by picking up your hands you will have to use your chest muscles to hold yourself up over jumps, which means you will stop falling on the horse after every jump. It will take a little getting used to and some time to build those muscles, but once you do, you will have a lot better control over what your body is doing.
This is what happens when you have democrats in office