As for Mayu's thoughts on Akito... I am grieved to note they have not threaded together in camp. So a lot of this is reacting to what Akito has done, that Mayuko has heard of!

While there are negative feelings towards him, Mayuko does not feel... personally slighted by Akito. He did ruin Hatori and Kana's relationship; that produces the core of what animosity she feels towards him. And in camp, Hatori evicted Mayuko from his cabin for Akito's sake. I probably essayed on this, so I'll say Mayu knows Hatori made that decision, and he did it to protect both parties... but still feels upset on some level that her home got wrecked. :\

But neither of these is a personal affront! Meaning there is hope for... something positive. She's not even a blip on Akito's radar, it would be unjust to just hate him and leave it at that! I believe the two could, in camp at a later date or post-canon, get along? She does respect his position as Head of the family, they do have personality points in common. But... I don't think Mayu will ever view him as "family". She holds that much of a grudge for Kana.

Haaa, I hope that makes sense... shall we go with your characters and their view of family?