Once more, with feeling:
1) Things started going pear-shaped after the March 7 update.
After yet another hour of troubleshooting, the latest version my phone now sees is Feb 27 and it appears to be working as advertised. The Play store still shows March 7 as the latest build but they've locked my phone off from grabbing it and lo and behold, we're back to where we were when things worked.
I honestly don't understand how this became a discussion about how I don't know how to phone. It's frustrating verging on insulting.
For the record? I have a 16-instance SIP gateway on 90-minute battery backup with a (not-yet-configured) failover from Comcast to Frontier that records voicemails and sends them as .wav files over email to hit my wife's phone on T-Mobile, Sprint, US Cellular or Wifi all because in Washington paging networks use the same frequencies and towers as cell networks which means they provide no redunancy which means I effectively needed to roll my own 5 nines reliability paging network out of off-the shelf componentry and fuckin'A, up until Google rolled an update (an update I've now spent five hours, six emails and fifteen bug reports unfucking) it all worked gangbusters without having to pay for two f'n plans. AT&T? GSM. Verizon? CDMA. TMO? GSM (and they share most of AT&T's towers). Sprint? CDMA (and they share many of Verizon's towers).
So sorry if this comes off as snippy but I legit assembled a goddamn 7-phone PBX in my apartment in LA to confirm all this shit worked and the problem isn't that the solution doesn't work, it's that google fucked up.