The state of translation extensions in Firefox is catastrophic. The useful ones got deleted from the store. As far as I can tell the only reason was to flex some policy choices by the extension store(?) team.
So you pretty much have to have Chromium as a backup if you ever need to research non-Anglo content.
I can see people moving to Chromium because of this and other similar problems with extensions being broken (like the tridactyl thing).
You can use userscripts (e.g. with Violentmonkey [1]) for Google Translate, e.g. [2].
Since you mentioned Tridactyl you might be interested to know that I wrote my own command to inject Google Translate on demand [3].
The extensions you mentioned were removed because they execute remote code. Mozilla are trying to tighten these restrictions [4]. I think Chrome is moving in a similar direction. I don't think that will affect the user script work-around as they execute in the page context, but I could be wrong.
Violentmonkey is very actively developed [1]. Greasemonkey isn't [2]. Tampermonkey is closed source so I view it with some suspicion. Otherwise they're all pretty much the same, as far as I know (I don't use them extensively).
So you pretty much have to have Chromium as a backup if you ever need to research non-Anglo content.
I can see people moving to Chromium because of this and other similar problems with extensions being broken (like the tridactyl thing).