There are several ways to do this depending on what you are trying to achieve.
- Use the LFO of the zone to Modulate the level of the zone via the mod matrix (do this for all zones in the preset).
- Create a mono LFO midi module and do apply it to the mod matrix of each zone via the mod matrix (similar to first suggestion).
- Do either 1 or 2 and then tie a quick control to the depth of the modulation to increase intensity of LFO, or rate or etc etc.
- Create automation controls to the level of the layer/zone and send modulating automation data to those controls.
For your other questions there is currently no way to automate any bus parameters by a user LFO but some FX have built in LFO’s and envelopes you can use. I do not think it is possible to control any quick controls or automation via LFO but this may be possible via scripting. As far as I know it isn’t possible though.