I think you’re underestimating how many we can teach during the years of rebellion and how much territory we’ll de-facto control in game 5. Obviously we can only fully implement all the new stuff in the areas under our control. Law enforcement and the army are also the most critical priorities to stock with former helot veterans in the upper ranks .
Besides, when it comes to reading and writing the yeomen, at least in our home area of the Rim are barely any better educated then most helots in these subjects. So tapping them for the police force would result in the same problems, just with slightly less loyal people. The merchant class/caste, at least in our starting neck of the woods seems like it would be too small to fill all of the crucial spots, and my mc would prefer them in the parts of the bureaucracy less concerned with the application of force.
Maybe the currently oppressed (but technically “free”) urban masses can be part of the solution, assuming we can win their loyalty and assuming their education and record keeping skill are any better than those of our rural yeomen, coming from a provincial backwater like we do, but they would be unfamiliar with much of the territory outside the cities, which would be a big drawback to placing them in charge of rural police.
If they would my mc would not trust them to actually enforce the new laws anyway, so it’s a moot point but there are likely to be much more like the “noble” mc who are barely nobiity anymore anyway and might have to take any paying job they can get post-revolution. My mc certainly won’t be subsidizing the priests and nobles any longer.
In ancien-regime France they obviously found nobles, or at least their lesser (and some bastard) sons who would, but that’s not a route that would sit at all well with my mc.
Most organizations tend to be pyramids, especially the military and law-enforcement. So the stocking will begin with the very highest ranks and work downwards from there. Obviously, I’m anticipating more success with educating some of our adult veterans then you do, but I think my mc would at least be able to find former helot veterans, now used to commanding large numbers to fill such positions as the provisional minister of police and immediately downwards. After that come the most loyal yeoman and merchant veterans, etc, etc, and like you I will stock the lower ranks, as in most of the common officers with former helots too.
True and my mc has little trouble with stocking the relatively vast middle ranks with anybody (except former priests and nobles) who can meet the criteria, but he’d need to keep the upper ranks loyal. So unless he somehow has enough loyal veterans that he trusts from the former merchant caste that’s still going to fall to the better-educated helot veterans.