Should the commons be connected?

Electrically, it would be redundant.

Why would it be redundant?  It sounds like he doesn't have a common connections between the two anywhere.

I guess I'm not sure what he has, but if it works, I guess it's OK.

I'm thinking it would insure the TMCC connection is complete to both distribution barrier strips without having to rely on the rails for it?  Would it hurt anything, like signal timing for DCS etc if I did jumper together the two common segments of the two barrier strips?

I'd connect them at the barrier strip if it were my layout.

I probably would too although it won't make a lick of difference.

And it won't hurt anything.

Kind of like deer whistles on cars. I'm quite sure they do not attract deer.

You sure of that?   I have a friend that has hit two deer, and he's had them for years.

I can vouch on that. One evening seen 2 deers in my headlights, their ears perked up, and ran directly in front of my truck. Got both deer, insurance company totaled truck. But had deer meat in the freezer, and a new truck with monthly payments. Never put them on again.