Σ(っ°Д °;)っ ye got a point!!
Yess! The part where cecil said hes never been ay the tower where the MC clearly remember he has is a big factor! Cecil is actually noah and just by the recent chapters, it proves that he is hiding his identity!
It's exactly what i was thinking about the tower but also with the story about the fish.
Little Cecil said that he doesnt like fish, but big Cecil have no problem to eat it. When the real Karen said to big Cecil she remember he say that to her, and Noah was angry, because it's him who doesnt like fish !
Big brain (〜￣△￣)〜
Everything makes perfect sense if Cecil and Noah also swapped names/identities.
That's why "Cecil" couldn't recognize that Karen was only pretending to be Ichika.
How "Noah" loathes the real Karen so much because she "ruined what he loves most."
And why the MC, Ichika feels more comfortable with "Noah" despite the years she's spent talking with "Cecil" in the mirror.