Merge into V-series supervisor droid[]
There is evidence that indicates EV-II should be merged into V-series droid supervisor.
According to Cynabar's Fantastic Technology: Droids, the model that replaced the first-gen EV was called the EV-II. However, Arms & Equipment Guide instead says that this role was filled by the V-series (it should be noted that this source does not state it to be an Imperial model). These are the only sources that say anything about the original EV actually being replaced, with other sources saying that the model was recalled and its motivators were swapped. The New Essential Guide to Droids states that the EV-series was relaunched as the V-series, indicating that the EV-series was effectively discontinued at that point. It must also be noted that a V-series droid appears in The Clone Wars: Act on Instinct (Unidentified Republic droid), which would only make sense if the model somehow predated the formation of the Empire.
Thus, it is likely that the EV-II was rebranded as the V-series after the Clone Wars when MerenData tried selling it to the Imperial military. The V-series cannot be a rebrand of the original EV with the intended EV motivator because it is explicitly stated to be a replacement model, setting aside the fact that they have completely different heads. The only caveat is that The Essential Guide to Droid mentions the existence of multiple replacement models. However, this is never mentioned in any other source, and we have two separate sources identifying what are ostensibly two different models as the replacement, one of which is a more recent source than TEGtD.
In short, the EV-II and V-series are both identified as the model that replaced the first-gen EV, we have a V-series droid appearing before the rise of the Empire (in 21 BBY), and we know that the EV-series was rebranded as the V-series. This means that the EV-II, the replacement for the original EV model, was rebranded as the V-series. Thus, EV-II should be merged into V-series droid supervisor.
I’ve provided the relevant quotes below so you can judge for yourselves:
Cynabar's Fantastic Technology: Droids: "MerenData remedied the problem by introducing a new version (the EV-II)) and recalling the defective EVs." and "The EV-IIs more than compensated for the personality flaws evident in the first generation EVs"
The Essential Guide to Droids: "But their replacement models (including an Imperial-issue “V series”) were unimpressive performers. The EV series was a financial failure."
Arms & Equipment Guide: "Despite a factory recall and replacement (the V series, which has similar attributes but a more tolerable personality)"
The New Essential Guide to Droids: "A panicked MerenData made every effort to recall the affected models, and even tried to relaunch the line to the Imperial military as the V series. Both lines failed spectacularly." - AV-6R7Crew Pit 23:08, September 6, 2019 (UTC)