Okay...it now works...sort of...
I still have to hit the mute and unmute to hear the call through the headphones, but now the other end can hear me.
I had to wind up using the stock headphones that have the 3 rings on the tip. Otherwise the mic gets rooted through the earburd on the standard earphones. Tried a pair of JVC's that I had with me, and I confirm that's what's happening. The JVC's recorded through the earbud while the stock headphones worked with mic on the phone.
Truly weird issue, but at least I found a, "duct tape," workaround until a new build completely fixes the issue.