Just wondering, why are you intereseted in learning how to do kip-ups and back flips?
They both are very technical skills to perform correctly, but once you get it there easier to do than walking.
Thats cool that you did a kip-up the other day, something that might make them easier for you. Work on your back flexibiliy as they require you to arch like a contorking cat, and make sure you are rolling onto your upper back to perform the kip as you push with your shoulder blades. dont just start motionless from your upper back.
For the back flip.
If you can do a front flip you are miles ahead of your self already. Back flips are 100 times easier than front flips because you can see your landing as soon as your over your head, where as with a front flip you cant see your lading until the skill is done.
You dont need a huge vert to do a back flip, it does help but if your technique is down you can pull one from just about any height.
I could sit here and explain every biomechanical movment you need to perform in order to do a back flip but that would be alot of info overload. So I suggest you get back to me on what you have been doing for your self and I can help you from there.
The first thing though, if you have not done so yet. You have to get over the fear of going over your head. once you get that you'll get it in know time.
Hope to hear from you soon.