Umareru pretty much gave you some pretty solid advice for this match up so i won't say much.
Pretty much any air grab or grab leads into a free summon gate. I seen a few that you missed. another thing is that zappa has pretty much no game on wake up, grab them if they get to close or backdashing are pretty much your only options. Summon gate is good occassionally but is easily baitable and you get punished hard for it if it doesn't land.
Sadly jumping with zappa in general is a bad thing, especially with naked zappa. Usually if you jump in the air, you are going to get beat out which is why his air grab is sick.
Also, when it comes to FRC on the ghost tosses, it is a very crucial part of the ghost game but don't over do it. I try to minimalize it due to the fact it literally will drain your tention if it is overused, making it a very bad thing.
Being able to react to situations is a huge part of playing zappa due to the fact he has four forms not including raoh that can randomly occur due to e-summons. This can either make or break your game.
Also, if possible, always try to summon gate out of a combo. A basic combo to use is 2p 2k 2h 236p. Also utilize you f.s as much as possible, it is an amazing move than can give you a free summon gate not to mention a ridiculous amount of control forcing your opponent to bend to your liking.
I would suggest getting down the basic mechanics of the game before going for huge combos though. knowing what each of a characters moves do be it a special, overdrive, or whatever is easily one of the best things you can do. Zappa is easily a difficult character to learn but just stick with it. It is definitely worth it in the long run.