These points don’t make much sense to me.
Why would you have separate setlists for each keyboard? What if (as is often the case for me) you want to use both keyboards on a song?
Scrolling through setlists is easy. You could use a system action plugin or set up a widget to move rackspaces in the Global Midi section.
If you want to jump from song to song as they are called out (not in order), that is a bit more involved. There are several threads (and I think scripts) dedicated to the topic. Also check out Dave Boulden’s Advanced Song Chooser addon (not free): Advanced Song Chooser extension
I learn faster by watching videos. I tend to recommend watching as many youtube videos as you can on setting up rackspaces, setlists, and widgets as you can. And, of course, dig into the manual as well.