SPOILERS
Well. I think Ending B here is impossible.
The whole story is about two people who were tired about being someone's second option. There's no way they going to choose their own second option.
Ending C is interesting but the story would be really hard to felt satisfied. It's like ordered a pizza and deciding just to eat the box.
So Ending A is an unstoppable train. But what Baxter needs to do is not explain nor apologize. He needs to prove that Mylo/Russo is his number one priority.
So far, Baxter had 5 of Mylo's photo.
1- First Mylo's photo was taken in Mylo's bedroom.
2- Before Holloween's party.
3- They do project at Bax's
4- Before album record.
5- one month anniversary.
I would assume Baxter wants to write a song about them like Mylo did?
There are a lot of options for Chapter 8. But I had a feeling that Emma, Liz, or Wyatt could be somehow a huge part of it. Something like...kidnapping them from home and locking them in a room so they can talk that kind of thing. (After Mylo and Jakob's 'conversation'...
Mylo/Russo and Baxter's relationship and how Baxter calls between Mylo and Russo is really interesting. Maybe I'm overthinking but I think Mylo Russo is presenting a duality of a character. Mylo is his vulnerable, emotional part. Russo is his logical, resolved, numbness part. The shell that he protect himself.
I like to think that Baxter is friend with Russo and falls for Mylo.