I really like this theory Nef! It would also really fit in with some ambiguouse stuff we hear about Obernewtyn, about the greenthorn maze being based on an earlier maze and the Master's mind being a bit of a maze in and of itself. Being a refugee from a near forgotten time would probably twist your head around a bit, and it would make sense that he would try to construct a little piece of his old world in the new one.
But if his mother is a descendant of Hannah - then she is a Seraphim already!
Except that in the land, the last name appears to be passed down along the male line. Hannah II would have had it because she only knew her mother, but not even her
children would have kept the name, let alone her children's children's children. Not to mention that I doubt Rushton's father would have been so keen on his mother if the possibility of their being related was so blatantly obviouse. :P
But then, maybe that
would be the reason for for Lukas being sent. It might be important that the misfits be aware of Rushton's lineage. In fact, that could be it right there. If Seraphim DNA is
important, then someone is going to need to know about it. You don't want Elspeth getting to the weapon machines with minutes to spare, being requested for a sample of Seraphim DNA and thinking to herself "Now, if only I knew someone named Seraphim...", meanwhile having a lock of Rushton's hair in her pocket! I mean seriously, that would suck.
If that were the case, then Lukas wouldn't have needed to be related to Hannah at all. He could have just taken on the name, Rushton said himself that many people took on new names after the time of chaos.
Maybe Louis isn't a relation of Hannah, but is an unrelated beforetimer, somehow mixed into the Reichler Clinic, who was frozen and took Hannah's name to help set things up for Rushton and the Seeker.