It is possible to do all the things that you want, regarding the one touch settings, that you have to save those into each of the User style (USB or internal memory, but this one is limited). Keep in mind that OTS is part of the style.
I have the S900 as a backup of my T2 and I have done much of what you mention, a piece of advice, I put my User Styles in the SAME folder of those registrations that contain them, that way is faster and better since there is not path to trace for the location where you have the styles/user voices/pads, etc.