Hi Darren just to further answer your questions.
A) Sadly for the software detect inactivity is simply a little difficult, and this is why all multi-player games are timed. The software does not detect whether the player is active, it just detects whether that player hits within that timeframe. And issues the penalty as a consequence. Yes fruestrating for the others, but just have a good chinwag in that time.
B) The Host can remove any player, for any reason , if a player wont start, I have no hesitation in booting them (or for any other reason lol). So that puts the host in control. If a player rocks up with an orange tick, I will just leave if I am not the host or ask the host to boot (if you know the host)
C) The game will start after all players have pressed start - if it is not starting someone is not playing ball, so go to point B, and get those steel capped boots out.