Keeper of the Lost Cities Theories!

Siblings?

I just recently came up with this theory and it had me thinking. I don't have a ton of evidence to back it up, but whatever. I hope you enjoy!

Theory: Marella and Keefe are siblings.

Evidence: 

                 I was re-reading the series, and I don't remember a single interaction with those two at all. Not a single word to each other. Only to the group. And I'll get back to this later.  

                  The next thing I noticed is their appearances. Blond hair? Check. Ice-blue eyes? Check. Very pretty/good looking? Check. (Well, all elves are, but Sophie said these were very beautiful elves when she met them) And with the eyes: There are so many shades of blue that I can think of that Shannon hasn't mentioned yet. Seafoam, electric, navy, royal, sky, baby, indigo, ocean (ocean eyes!!), sapphire, and berry blue along with tons of others. So why would she choose two characters to have such similar features? 

                    Okay, now we're back at the first part: Shannon may have made it out to seem that they didn't really know each other, but knowing her, what if she wants them to find out their siblings or something. Or maybe they already know and don't want to tell anyone. I'm not sure. 

                   And another thing: Their personalities. Sarcastic, brutally honest at times, but also cares a lot for their friends. Doesn't like being left out, and has a bad background. Marella a pyrokinetic and Keefe's mom is part of the group trying to kill them.

                   Lastly, Keefe's mother? Evil. Marella's father? My theory is evil if you've read my other chapters. What if they were originally married and then Gisela wanted and empath for a son for some reason, still not sure why. Or maybe they wanted to make it seem less suspicious and married a person of very high status that no one would suspect, and a person who can't think straight because she fell off a building. In my opinion, those two people would be the least likely for people to assume they're married to anyone evil. Anyway, in all, I think they're either twins from Lord Cassius and Lady Gisela (and Marella was put in Caprise's care) or they're half-siblings. Keefe from Lady Gisela and Lord Cassius (because he's an empath) and Marella from Lady Gisela and Caprise's husband (my theory is he's Trix).

                     Let me know if you're kind of confused because I don't think I explained this very well. I'll try and explain it better. Does anyone agree? Thanks for reading!

                     P.S. Only 159 days until Unlocked comes out!!!!!!!!

                     P.P.S. I kind of have this theory that it's Marella who wakes Keefe up. Maybe that's my wishful thinking, but having Keefe wake up to a sister he didn't know he had would be so cool! Buuuuuut I'm also okay with Sophie waking him up!!!!!!!!