As we know, Daniel and his family have what can be called an "extended family." Though they're not Daniel's mates, Sheal, Rolian, and Felucia have joined him in helping to install peace across Eden. Mr. Gordan even mentioned that Daniel may end up having concubines join his family.
With this in mind, could it be possible that Daemon and Max may ALSO end up taking on additional members who aren't harem members but still helpful/caring friends and allies?
Perhaps someone could become loyal to Sasha or one of the girls and assist Daemon in finding the keys. Maybe Max could become a sort of "big brother" to a little monster girl. Perhaps a new character will emerge and serve as a go-between for the harems. Someone who is both friend yet also not a full-time member.