Why do I get the feeling that Ayane is actually playing them? Ayane could be the one lying. I mean Yasu give her an option to talk to her god and we don't know what happened. I find it strange that Maya and Ami both get a calls from eachother. Most importantly, Ami and Maya were the only one arguing with eachother. Not to mention , Ayane is afraid being lost/not part of the Rooftop gang and losing her memories. Also, she knows Maya doesn't like her. Not to mention, she flaunts her relationship with sensei to Maya.
Simply, it would be Maya as well. Considering she is extremely manipulative and dangerous at times. We have seen her yandere look during Noriko debut. Living in a loop for thousands of years and finally getting Sensei back is definitely going to make her to do reckless and dangerous shit.
As for Ami, her being a yandere is very likely and she makes it very apparent that she is possessive and mentally unhinged. Also, it seems strange that Ami could hurt Sensei? Considering so far, she is the one keeping him from ending up dead or blowing up.
My bet is on Maya being the antagonists but it be hell of a plot twist if it was Ayane