Tsumugi and Tsubame relationship

I've been going ahead with Tsumugi's scenario and it's now certain that it's a continuation from her specific ending. In this scenario Yua isn't there as she disappeared to allow everyone else to continue with her life and Tsubame/Tsumugi are living their life at the best. Tsubame is under the assumption that Tsumugi doesn't remember about Yua, but that's just a lie as she does remember.

Just as they're going through their life normally (with some nice comedy scenes with Alice worrying about them as they look too much like an older couple), they discover that Castella (Yua's bird) is somehow back which shouldn't be possible as she're strictly connected to Yua and couldn't exist without her. Does this mean that Yua is going to come back to deliver an happy end in this reality too? That would be a nice touch to make all the routes "canon" and just different parallel world and all with a happy end for everyone, but let's see what they do.

Right now Tsubame broke his four limbs protecting Tsumugi from a fall and is now being pampered by Tsumugi, quite cute scene. She's become ultra protective of him after the event and it's quite cute to see their back and forth as everyone else is instead kind of "what are these two doing?"