Is Harbaugh allowed to communicate in-game?

Yes.  Yes, it was.

As I tell my students, there are no dumb questions. Only dumb people. 

How about a pregame talk that is prerecorded and played to the team at the usual time except on a video monitor?

I'd bet that would work.

Not necessarily.

Y'know how some people—not saying it's me—yell at the screen? Of course, no one we're yelling at through the screen can hear us.

BUT doncha feel that somehow, regardless of the science, that the sense of what we're yelling gets conveyed to them somehow?

So unless the suspension includes no yelling at a screen, Harbaugh is communicating the way the rest of us do—and they feel it.

Even if he was, the telecast is on a slight delay with real-time; that would interfere with internet coaching or what not.

Bet - Sarah Harbaugh would have a problem with that. 

Just like our locker room

That’s awesome. I’ll swing by her house - would be pretty cool to meet Coach Harbaugh and watch the game together!

this question is about Harbaugh not  Josh gattis 

I'm sure he'll get a police escort to the locker room after Michigan wins.  He showed met them in the LR at both PSU and UMD after the game.

He’s suspended for the game.  The 3 games are over when the clock hits 0:00.  I think he can be there then. 
I would not be surprised if you see him in the locker room.  Arlington road to the stadium is about a 7 minute drive if you’re not speeding. 
 

It would be awfully nice for him to show up at the venue with Santa Ono after the game to celebrate with the team and then for Sana to post a recording of himself telling the NCAA to fuck off.  Followed by another recording of him with Harbaugh holding up the barely dried signature page on a revised contract -- this time with both of them telling the NCAA to fuck off.