I agree that it's the super obvious choice and it may very well be that Bella is the scheming witch in the background... but then again, why be super obvious? Maybe the writer is a fan of Rian Johnson and wants to subvert expectations?
Please. Anything but that. Hit me with an obvious reveal, so obvious that a child could have guessed it, I'd take that over having my 'expectations subverted'. I've had enough of that for one lifetime.
But why would Jolina be involved? Unless she and Bella are an item? Of course the two ending up in the beach house may not be a coincidence. However, that depends entirely on the MC's choice and Jolina and Bella can't know what he will decide. Jolina also (apparently) leaves town if you break up with her (could be a ruse)? I cannot see the Jolina / Bella angle here.
Jolina is the linchpin to the plot, the email was sent from her shop, which started everything. Jo and Bella might be an item, or it might just be a professional relationship, though it's been suggested several times that Jolina has a preference for women. The fortune teller might have also alluded to it, the sister and her blonde lesbian more likely refers to Jo/Bella than Katie/Debbie.
Also, if you're on Jenna's route, there is a scene where you spy on Jo through her webcam and some super detective in this thread figured out that it's from Elaine's kitchen.
Not to mention the fact that Bella and Jo are probably the only LIs who never take no for an answer, for most other women, you get a simple 'not interested' choice and romance is never brought up again. But these 2 girls just keep going after him over and over again. I mean come on, I know the MC is a good looking and smooth talking charmer, but it's still a bit odd, especially for Jo who barely knows the MC.
Lastly, she only brings up leaving town if she is in a relationship with the MC (probably to test how serious he is with her). Otherwise she only asks if he knows any cheap motels in the area and doesn't bring up some supposed job that she has taken on the other side of the country. I am pretty sure Jolina isn't going to disappear from the game even if you don't invite her to the BH.
And sure, Elaine is most likely also looking out for herself. But I don't blame her. Everyone wants some security. The MC already has that, he will always have a place to stay and 100k is at least something. Being a little selfish does not mean you are evil though. And she's open about really wanting the house. I think she's honest when she says she will make sure the MC will get some money if she can help it.
I agree that Elaine has every right to look out for herself. But it's rather hard to sympathize with her considering how unceremoniously she yeeted the MC, a 19 year old kid who himself had no security, out of HER house. Not only that, but she went above and beyond in being evil and petty towards him, when she told him that even if he has no means of residence and is really struggling, doesn't mean he can return.
Even if it truly was because of her guilt and shame, still doesn't justify her actions. She could have let the MC stay at the Beach house or done 100 other things that didn't involve kicking a barely legal adult out of his own house immediately after his father's passing, without a support system.
No matter how sweet she acts towards the MC or how many of his football games she attended, she can never live this down. Also, I am not certain how sincere she is when she offers the inheritance money, remember, she will say anything that will ingratiate herself to the MC, so I'd take her offer with a grain of salt.
About Theresa, remember "Chekhov's religious nutjob rule aka Chekhov's gun"... if the plot mentions some super religious woman the father had a fling with... and then you meet ONE woman in the entire game who fits that description... chances are she actually is the one. And maybe Theresa's plot was for her son to stalk Jenna, she counted on the MC to intervene (which is not too far fetched) and this way get into contact with him. She is super thirsty when they meet, maybe that has other reasons than just being crazy. I ignored her entirely of course. So I can't say what happens when you submit to her craziness.
The most important fact to keep in mind: You don't hear the description and THEN meet the woman, you meet the woman and then hear the description. And from whom? And who introduced you to the woman in the first place? I'd say it's more likely there is no religious nutjob that the father had a fling with, and there is no other son.
It could be possible that she sent her son as an attack dog (heh) to lure the MC, but I think it's too farfetched even for this game. The odds of it all coming together like that are way too crazy, especially from a crazy person like that.
But her romance path is surprisingly sweet, as much as it can be with an over the top religious loon. She's just a lonely and repressed person who is looking for some companionship after she wasted the best years of her life raising an absolute societal reject like Tommy. And she has to reconcile her beliefs with her attraction towards the MC.