@1) I have complete KNX regulator xcf available, where you may
- control set points
- view real values
- switch different regulator modes (absent, comfort, night, freezeprotect)
- switch speed of fan coil
- switch between heating and cooling function
As every KNX regulator has it's special features, it would be good if I knew which one you are using
@2) You may (almost) use as many switch buttons and analog sliders as you like - the limits is given by the screen size. You may just copy the pages for using more elements.
@3) Yes, thanks for your request, I will do development for KNX interfacing, send me a personal e-mail (best with your phone number)

Best Regards