Ok -- I forgot to actually test changing an e-mail address -- I was just happy that you could get into Control Panel without an error.
And I only "disabled" (rather than removed) the Name Formatting thing -- so I figured it would still allow the Control Panel to work (which apparently depends life and soul upon that first field...)
I'll keep talking to the author and figure out a solution to prohibit changing the formatting of one's user name, while allowing the Control Panel to work.
Anyhow, it works now. I tested it even! :farmer: