Now for questions:
I actually really like your idea for the coms expert, Ebb. Would it be a 10% chance of every PM sent, or just those sent by a specific target? It would help solve the 'buffer post' issue you brought up. (Though I have to admit, I was looking forward to seeing people send one another or themselves 'decoy PMs' each night.
My original idea for that roll was to have them be a coms jammer, and pick a player each night that couldn't PM at all until their next phase, but then I thought that wouldn't be fun at all for the person jammed, and 86'ed it.
For the HR specialist, I figured a special role would be any of the unique Patriots, basically a role that hunts for people they can trust. I can see why you'd be concerned though, it may be a bit OP. The battleship idea you had may work best.
Lastly, the medic can only save people attacked during the night phase, as saving someone during the day would require a public revealing of their role, something I'd like to avoid in this game. On that same note, people won't see it happening, I'll simply announce there has been no kill that night. It'll be up to you guys to discuss and figure out if that's because of the medic, the bodyguard, the recruiter, or possibly because The Unplugged have been eliminated...