Yes, upper Chan 1, lower chan 2. As for changing them from 1-2 I can't answer that.
Presets are kinda odd in that they work like the Vintage B3 preset keys, one organ different drawbar settings. You cannot have different organs on the presets, only drawbar settings. (You have no idea how much this confused me at first... dont even go there).
Incorrect, that is exactly what it is! A portable computer / sound module with a usb midi controller attached. (all wired inside of course, I had a look )
Better than the SK1 but like you say it is not weighted but certainly triggers sounds MUCH better than the SK1 ever did when I had it.
That's all I can answer hope it helps some what.