Not really enough place for it. There is a concept to add an "advanced mode". Instead of just setting the filter/insert there will be a third option name "Quad" or something, which adds a stack of four settable per voice inserts. Similar in control to the FX stack (including sorting). I hope it will be added some day :D
Not possible for now. Most of the time you can automate LFO or Sequence Level, or envelope sustain and so on. It's not planned to modulate automation depth, but there will be an additional "via" or modulation mapper, which will address this in another way.
Right. You can unzip these packages. Edit the images and zip them again (don't compress, just save). Runtime colours can be defined in style.ini. Don't forget to edit the name in meta.xml, so it really shows up as additional skin.
Has anyone of you played with PM/AM from Oscillator? Didn't get much feedback for it, even though it's basically a three operator FM module with a lot of new possibilities. Show some presets if you like : D