Io assume Jonah Levin will most likely become another bondsman turned ally for the wolves. The way he was portrayed sofar is of someone who is extremely fair to everyone while also being ruthless enough to do what is necessary (to a certain degree). And imho alaric will need someone to be the conduit to the Terran population. Given how small the Wolves army is he could never survive an uprising of 10-12 billion angry Terrans. Japan should be a warning to anyone.
As much as I’d enjoy the 12 billion angry terrans causing problems… I don’t really recall angry local populations causing meaningful problems for occupation outside of one novel. It’s silly, it really is, but if we follow in universe precedent, Alaric shouldn’t have huge issues with Terra itself.
That said, the tiny glimpses we’ve seen makes me think Alaric wants the clanniest of clan Leagues, which could include instituting the caste system full bore on Terra. Which, per EA, even the Wolves’ “light hand” in the empire made the civilians hate them.
Could it be a plot line? Yeah. I don’t think it will be.
As for Levin and others in command helping with stable rule, it’s not an impossible story, but it would require Alaric wanting to compromise and reach out to the Terran civilians. I’m not 100% on all of Alaric’s stories, but I don’t recall him ever treating locals as more than serfs. If somehow Alaric changes tack for Terra (character growth opportunity?), maybe some of RotS command could cooperate with the goal of “stop the fighting.”
That said, Levin’s a soldier. I’d more expect a Republic resistance assembled around him to try to do something. Given the magnitude of forces in the area, I’d expect it to accomplish nothing meaningful. At least not unless the RAF turned merc and all the unaccounted for line units rallied to him.