first sashay (gallop) with your leg that feel most comfortable to you.
next take your leg that you sashayed with and hold it in passe.
then while your leg is in passe you are rotating your body in the other direction so that your body is now reversed.
now as your body is in reverse and your leg is still in passe, flick your passe leg back as you flick your remaining front leg forward.
that's how you do a reverse leap.
spring on one foot and change feet
jazz shoes are called jazz shoes because you use them for jazz
Because you are dancing to jazz.
If you mean different catagories or styles of jazz there are a few different one that I know of. There are Street Jazz, Mordern Jazz, Lyrical Jazz, Funk Jazz, Ragtime Jazz, Dixieland Jazz, Freestyle Jazz and I'm sure there are many more. I would try to do a little bit of more of research if your really interested in it.
Funk jazz is just like jazz but with a combinition of hip hop