On the first page is a list called "LI list" (under EXTRAS). You can find there all relevant girls and if they are love interests, fuckable or not. The list can be changed in future.
Short: Amber is a beauty, she is believable, acts as a psychiatrist and as Bella's mother. And the most import is, she's a main LI. Different routes too.
Amber is smokin hot and she has a vested interest in helping the MC fix his problems - not just as a psychiatrist, but also as Bella's mother.
I think that the trip Amber and the MC will make to the cabin will be pivotal. It is a place where secrets will be unlocked - some of what happened in the past - and some emotions for the MC, perhaps overwhelming, will also be released.
I also think that it is the right place and setting for Amber and the MC to have an intimate encounter.
I could see some roleplaying with Amber asking the MC to pretend that she is Summer and to walk her through the day. I think that Amber will stay in role as Summer and as day moves into night and the MC and Summer kiss and fool around, she will stay in character through most if not all of the roleplaying.
We have every reason to believe that the MC and Summer were kissing, but what about petting - clothing on or off; what about some oral - above the waist or full on.
If Summer gave/received oral in the flashback, will Amber stay in character through this or will she break character (and does the MC being Bella's boyfriend - the choice to kiss/not kiss Bella on the hill - influence that decision).
Finally - I believe that this trip to the cabin will result in some level of breakthrough for the MC regarding being able to be aroused by a woman
(something far beyond what Nami got by giving him a quasi ass job in the hot tub at the end of the night at Nicks) .
Will the MC develop some level of emotional attachment to (or sexual desire for) Amber because he ties his Summer memories to Amber memories due to the most recent trip to the cabin?
If this happens, does the MC start greeting Amber (in private) with kisses and petting, or when Amber holds the MC when he is in a therapy session, does he end up kissing and pressing for some physical intimacy now that that door has been unlocked?
Through all of this, how much of the activities does Amber note in the MC's file - one of the files Bella is most certainly going to snoop in since she wants to know what is going on.
I think Amber knows some of the snooping that Bella does so she will lay some breadcrumbs in the file to help Bella and the MC if they are in a relationship; if Bella and the MC are not in a relationship, does Amber provide breadcrumbs to lead Bella away from the MC, especially if Amber finds she is starting to have feelings for the MC beyond those of his psychiatrist or as Bella's Mom?
There are So many possibilities here and the fact that the MC is Absolutely Not a horn dog will add to the likelihood of increased intimacy with Amber during the cabin trip. Amber will know that the MC is not playing her to get in her pants - he is truly a man who needs her help and her commitment to help the MC even if it requires an unconventional approach that could lead to unexpected levels of both physical and emotional intimacy between Amber and the MC.
Ocean has quite the story to tell here!