It seems like they took the eye bug control thing as far as it could go as a plot device in terms of controlling/infiltrating the good guys, and now they have to come up with a completely new thing to keep the show fresh. But at this point it seems totally contradictory and senseless. Cochise mentioned something about a power source, unwilling to discuss further, so my guess is the Eshfeni need un-eye-bugged humans as the energy "source"--Matrix style.
One thing I was never clear on, is the Hitler youth program in the same place as where Maggie, Lexi, et. al. are. I don't think we ever saw the two youngest sons interacting.