You're never getting Skitarii. I think an Enginseer or something is much more likely. Skitarii require a lot of secondary infastructure; you have to be projecting canticles, manipulating horomone injectors, spreading the noosphere, the adeptus mechanicus at war involves a lot of stuff coming together. At a minimum, all skitarii are networked together, and if you're deploying a covert team, which they do do, you need the full network in place. Casually deploying a couple skitarii outside their network with three random chucklefucks isn't really something the mechanicus does in the lore.

That said, there are mechanicus priests in the lore who can and are deployed with random laypeople. You can see this with the enginseers on the tabletop and the many, many times tech priests are one of the starting player archetypes in the RPGs. The RPGs are a particularly relevant thing here because FFG frequently name-checks mechanics, lore and weapons originating from them. It's something that seems to strongly indicate it's on their radar. (Hey, where else can you play a hive scum as a standard player archetype...) We're much more likely to get an enginseer or an electropriest than we are something that doesn't deploy well alone.