There is absolutely no way they don't figure out what we're doing and freaked out and try to Purge us as a possible chaos cult if we go recruiting. Not saying it is necessarily a bad idea but it is a consequence.
They're not
that good.
Now, I absolutely guarantee the longer we stay in one place, the more likely some rando hero-type character stumbles onto us and calls down a clusterfuck on us. But that kind of heat takes
time to build, and the Imperium is--on the whole--very slow to act and not actually that good at noticing fractional rounding errors of the populace just up and vanishing unless it tends to come with "And everyone around them was ritually murdered in some strange fashion". Genestealer Cults for instance are vastly more obvious than what we're planning to do (And snowball up faster), and most of those tend to hit critical mass before anyone notices what's going on (Unless it's a strategically important world anyway)
Now, I will admit the longer we stay in one place, the more likely something
just happens to stumble across our operations no matter how well we hide them, because that is the story of the Imperium in 40K. But the quieter we are, the harder it is for fate to maneuver a bloodhound into our path, which means it takes longer.
I would probably say as long as we don't get caught up in some disaster (Easier said than done, it looks like they've already bunkered up), we'd have fifty years or so. If things
do get spicy, we'll have considerably less time, but we'll also get more XP and better access to opportunities.
Now, what we
have noticed here.
A) Flipping someone in the actual governance is
literally impossible. For all that these figures seem to be corruption catnip in universe, that doesn't seem to apply to us (As we learned here when the junior officers commanding a rando shuttle were 100% impossible to convert and in fact did everything in their power to try and kill us, well past the point where it meant anything) The implication seems to be that the Imperium is
extremely well optimized against 'Soft' subversion (AKA "Other ordinary humans playing silly buggers"), which comes at the cost of them being
extremely vulnerable to 'Hard' subversion (AKA 'Anything capable of forcing them to take a single forbidden action, at which point you don't need to control them anymore because their will breaks and they rapidly turn that fanaticism to their new master out of guilt'). This appears to be an intentional design to encourage said hard subversion attempts to become flagrantly obvious very quickly (Because there's nothing so prone to making grand gestures as a new convert), rather than piggyback off of a soft subversion and hitting critical mass before they reveal their true form and are too strong to be pinned down by a small force.
TL;DR: Imperials being insanely indoctrinated and yet prone to turning that fanaticism to the cause of the first person who forces them to break their conditioning is a feature, not a bug. It's a big problem for us though because we can't break through that fanaticism barrier without taking steps Eris would find repugnant. Fortunately, this conditioning is mostly focused on people who have any real influence, as we've seen from our mild success with the impressed crew of the shuttle. People who fall into the margins have the passive conditioning, but it's not strong enough to override "But I also want to have a hot meal and a safe place to sleep" instincts, which are the angle we can leverage.
B) We need to take
extreme caution with regards to grabbing Psykers. Because chances are if
we have identified one, so have the government. And there's no bigger red flag that the Imperium takes
extremely seriously as Psykers going missing rather than being burned at a stake/murdered/imprisoned until a Black Ship picks them up. If we have to go hot to liberate some, we need to prepare to leave and never return pretty much
immediately, because that's the kind of thing that gets full Inquisitors making time to peel over everything with a fine toothed comb, instead of leaving information networks and acolytes to gather data passively, and while we are very good, Inquisitors are
literally magic plot devices in universe, even if you set aside their access to the best agents and best technology the Imperium can muster.
C) Aside from that, the general information is a good move to pick, it's low threat (Everyone is supposed to know this after all~~), gives us access to figure out who might be flippable. There is a risk of course that someone takes a basic question being asked as a sign that we're an imposter (Because everyone's supposed to know that, you know?), but that's relatively minor since presumably, our operatives are halfway competent--and we got our basic fumbling done with the shuttle folk.
What this means?
We absolutely want to stay the fuck away from any of the Adeptus Terra. They are
at best indoctrinated enough that the moment they realize we're non-Imperial they'll do everything in their power to stop us. At worst they're already corrupted by some other power and will seek to suborn us to their true master. Grabbing a
single one is a full plot arc--with commensurate rewards no doubt. Not something we can get just from regular recruiting.
We do want to have a strong presence in the underclasses, because these are the ones who are most vulnerable to breaking their conditioning without needing to step out of line. These are also the areas most likely to churn out Psykers who aren't instantly identified (And thus getting us red flagged if they disappear)
We should be ready though to make a move on targets of opportunity. The Imperium is lousy with heroes and people favored by the fates, and grabbing one of those before some other power claims them is worth being able to never come back here again.