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.
Theyre such a teaseeee AAAA JUST KISS AND GET MARRIED ALREADYYYYYY