None of those questions can really be answered unless you explain how you wish to be using your keyboard, like what style you want to learn. There's a huge difference in wanting to learn basic keyboard skills to employ in electronic-type music or wanting to learn keyboard more like you would learn a piano.
Also, do you play any other instruments or what is your musical background like?
I've been playing piano for about 13 years but to be honest I don't know much about keyboards and usually stick to piano! So if you're wanting advice on technical stuff to do with keyboards specifically, I won't be much help, but if it's music theory and playing the instrument you're talking about then I can indeed share some wisdom
