@Oberon: Color me very red regarding the highlight bar on the pamac dropdown menu.

I know I restarted E each time after changing the theme, but apparently a complete system reinit was needed. When I booted in this evening, everything was functioning correctly.
@fassil: Thanks for the thought even if MedNight was not the solution.
@khalismur -- and other dark theme lovers. One reason I loved the MediterraneanDark and MediterraneanTribute themes is that they did not use pure white for the letters but a very faint grey. As a result, even when integration was not perfect, the letters would still be *just* visible -- enough for login and other purposes. For E users, the MediterraneanDark theme was also a very close match to the defunct e17gtk theme.
I have now integrated the chrome folder for Vertex-Dark in Firefox on my machine and all is smooth sailing. Works super with FF!
(BTW, Vertex is not the only dark theme to provide FF chrome folders, so if you prefer something else *and* it gets fixed, look for a readme and/or chrome folder in with the other theme file. Vertex is the first I have seen to put that folder in a FF subfolder of themes, perhaps as a new gtk3 standard?)
@philm: I neglected to say so earlier, but thank you for updating python-efl. All E users with econnman should now have it working again!