Wow, this is super interesting. I don't know if these sequels would have been successful (premise seems removed from the realism that made the published books so great), but if anyone could pull it off, it's Butler.
It'd have been a sad but potentially interesting critique of power to show Olamina become a darker character, as was suggested. Idk how I feel about the next book jumping to Earthseed having fulfilled its mission (in part) - seems like there'd need to be a transitional book with them making all the preparations under potentially new leadership first.