I don't know, but I've got a feeling that Ichika is actually Rena. Ichika knew that the photo was from Kyoto [Fuutarou told the story to Itsuki. Itsuki could then easily act as Rena.] and I don't think anyone has mentioned this, but the box Itsuki was moving contained some clothes that ICHIKA doesn't use anymore. And what clothes do we see in there? Mh'm?
This is just a Negi bait. I know it...