I’m on vacation so can only reply briefly.
a) If you send main out to Performer cue, Performer would hear himself with a huge delay. You can also choose what Performer hears in the Control Room, default is cue but you can choose main or other input like CD player or whatever you create in Studio settings. Read the Control Room section of the Cubase manual.
b) if Performer uses direct monitoring, you can simply mute his own channels in the Performer Monitor, only drawback is you can’t use built-in fx properly then.
c) use the “Create Performer Track” function or duplicate exsisting Performer tracks, then cue sends are enabled automatically. Otherwise you have to set cue sends manually, but tha’s true not only when you use VST Connect. Control Room offers some handy functions for multiple cue settings, read the manual.
d) sorry for beeing insistive about using “Create VST Connect”. I don’t see why it shouldn’t work in your case, in addition may want to mute Performer Monitor channels because of direct monitoring. If you have to raise Remote Latency you have a weak connection. " Have to Turn on monitor" (that’s not VST Connect Monitor, it is your studio main monitor like with any other mixing console) is mandatory when using Control Room, but we’ll check if we can look for that with the Create/Repair VST Connect function.
e) I will check how disconnect can happen if it works fine, seems very strange. How did you set "Remote “Latency”?