Getting an iPad Pro 9.7 inch (or iPad Air 2) tomorrow. Have to ask a few things

So, I'm getting an iPad Pro 9.7 inch 32GB cellular tomorrow at $30/month for a 2 years installment payment. $20 for the cellular package, $10 for the device. I won't be able to change my tablet for 2 years then. There's another offer to get an iPad Air 2 16 GB cellular for $20/month, but the thing is, the device fee is $0 for that, so i can change it any time after 6 months have passed.

Which deal would be better?

Also, this will be my first Apple device ever, so i really don't know what you can and can't do on it, coming from an Android device. I still have my Android phone, but really like iOS too, because of how polished apps are on it and how all developers seem to make apps for iOS and all. I am really attracted to the abundant animations on iOS too.

Is there any other pressure sensitive stylus for iPad Pro besides Apple Pencil? It seems great, but being a college student, $99 isn't something i can easily spare on a stylus.

Also, please tell me what are some of the really unique things you can do on an iOS device. I plan to use it for photo editing and music making (and art too, if i can save up money for the Pen), so any example of stuff you can do in these fields would be great.

This post is all over the place, but i hope it will get me a good introduction to this world. Thanks!