Tom,
1) Can't help with that, but I'm sure Hood, or someone here, will have a solution.
2) OK, so if I understand correctly, you basically need to offset the tool position when using the disc, right? If so, you can do this in the post. You'd have to modify the OnToolChange method, so the post knows when you're using the disc tool. You'd then need to modify all the motion methods (OnRapid, OnMove, On Arc) to add an offset to the commanded positions before outputting the moves to the G-code file. If you have programming skills, look at the post you're using, and it should be reasonably self-explanatory. Make a copy of it, and start modifying it. You'll get the hang of it pretty quickly. I've modified the hell out of mine....
3) OK, an external control panel can be controlled either by a macro, or a "brain". Watch the videos on the Artsoft website to get an idea of the capabilities of these.
4) OK, there is a button script that controls homing. Go to Operator->Edit Button Script, and click on the Ref All Home button, and it'll bring up the existing script, which you can modify.
Regards,
Ray L.