The concept is really interesting but it's questionable one would be able to recruit a regular citizen, no matter how able and experienced, into a government organization just like that. Even the most able individuals need a background check and, even more important and what's currently ignored - some idea of what they're getting themselves into.
The Screen Citizen job is meant to represent the process of background checks and carefully revealing to the citizen a sense of the scope of what they're getting into. The ones who are ineligible are represented by the sizable number of outcomes that describe their issue (a lack of discretion, a criminal background, a lack of talent). Keep in mind that the stock of citizens you're facing in these missions aren't average people off the street like the civilians in terror missions and such are—they're civilians who've gotten wind of the paranormal happenings going on in the world and have banded together into leagues of independent investigators and vigilantes. As the mod's chances are now, less than a tenth of these people are considered to be roughly equivalent in loyalty, athleticism, and professionalism to the agents you recruit from intelligence and investigative agencies around the globe.
In the second version I'll rewrite the research article to convey these points a bit better. I'll also probably make the chance of a recruitable soldier even lower, but make the other outcomes more rewarding and less punishing. I plan on bumping the engineer hours for each screening up to 120 from 72, to better reflect the difficulty of the screening process. Under these numbers, it would take a single engineer 5 days to do a background check, interview the citizen, and carefully reveal to them what they need to know.
I still think it's very important to get code support first which so the game could track face and other qualities of the person. No feature that requires external fiddling (like save editing, manual modifications) is a finished, decently working feature. Even fluffwise, brought above example of "we turned this caucasian lady into a burly black man" would be a huge stretch even if someone would try to improvise fluff for it.
Especially since the point of it is to recruit those particular individuals, not merely be able to pick them to get some other, random individual added to the roster.
I wouldn't say that the purpose of the mod is to recruit specific individual citizens. I'd say my motivation in creating this mod was to:
1. Add an interesting feature that expands the purpose and rewards of League missions
2. Add a feature that uses the new randomized production feature (which I think is so gosh darn cool)
2. Provide a mechanic that aids the player in imagining a backstory for recruited soldiers gained from the screening process
The code you're describing would first require a broad range of qualities to exist in civilians that only exist in soldiers. Civilians and enemies don't have a race or gender other than what their paperdoll, sprite, and sfx depict, and those paperdolls have absolutely no variety in facial appearance. Citizens also totally lack generated names, nationalities, and randomized stats. If code existed that gave civilians those qualities, that would be pretty neat, but I don't think anybody will take the time to write this (I doubt OpenXcom could even support this without breaking a whole bunch of things).
Long story short, the only viable way to give those faceless, nondescript civilians an identity is to make them a soldier and use the identity randomly generated for them or to manually create one yourself.
Assuming you finish the mission with no civilian casualties, you're going to be screening these captures in groups of around 4-12, depending on the particular mission. These citizens don't have a distinct identity to begin with, and you're going to be screening them in bulk, so I don't think it's a big deal.
When you screen 10 concerned civilians and only get one potential agent, and the agent ends up being a black man, you don't have imagine a white woman transforming into a black man. You can do the much, much easier job of imagining that the only member of that civilian league you recruited was a black man. And if you really, really, really wanted that soldier to have been a white woman to represent a particular civilian that stood out to you, you can make that happen with about 10 seconds of clicking.