Doing these one by one.
In the can't jump replay you simply have to get your left foot a bit closer to the ground before launching off (also don't extend the glute too much otherwise it's rather pushing you to the side then forward). You can decide how much you'll splin with your hips movement. I held them at a specific point to get a rather straight jump, you can contract them if you want to flip over him. Also you need some hefty arm movement which lacks in your version. you can try to lower the shoulders and see how far less you'd jump this way. When jumping off there extend your pecs and raise both shoulders for maximum jumps. Made a quick example of these adjustments.
https://app.box.com/s/aue9rvndhnt41pfdjro2
For the tricking, you are relying on single joint movements to initiate the trick and then move on from it. Which is the normal procedure while learning to trick. In your case that's extending the knee in order to jump. Advanced tricks require you to have a solid stand. I think people call it horse stance nowadays
I don't know why but from there you swing your arms with your chestrotation and raise your shoulders to jump. Relax or extend knees to further improve your launch off.
Also, little tip, landing on an extended knee is a huge momentum killer most of the time. Tricking is a lot about landing in a position from where you can immediately start the next trick. So you have to hit the right amount of height and spin. Also I prefer to land on contracted or at least flat ankles since they provide a better grip most of the time and look a bit more realistic.
For the ariel replay I'm assuimg you are referring to your launch off. Slamming your leg into the ground that way doesn't look very realistic indeed. The whole opener doesn't allow an easy improvement though. Your left leg is coming already extended on the ground which doesn't allow you to push it into the ground more. This makes it a bit useless. You should have rather tried to make your step with the other legt first. Since you are already swinging your chest and arm accordingly.
Like this:
https://app.box.com/s/yab5uxgba0kkkawyhsqk
You will actually have to be careful with this start since it already puts your upper body behind your legs. That's tough to recover from. Normally you want your upper body in slightly in front or above your legs. You can control that mostly with your hips/glutes (depending on axis), contract hips to bring your upper body forward again.