OK, that worked for five months, but now something has changed and devices are getting renamed again.
My OS is Ubuntu 16.04 LTS. It continued to work after upgrading to 16.04. Whatever changed was from a relatively recent update.
I understand the logic for persistent interface names, but they are an utter disaster if you're trying to use a single system image for multiple systems, doing something moderately complex like configuring a machine as a wireless NAT router, or, gulp, both.
Any help would be deeply appreciating.