Just beat it, so this was first time beating any version of SH2. I got the "Leave" ending.
Without reading too many theories, here are my newbie thoughts on just what exactly is happening, and I'm curious how it aligns with all your interpretations. Or if I'm totally off.
Silent Hill: Is a shared purgatory that's a blend of a real place, some kind of higher power's hell, and projections of the inhabitants' minds. It invites those who want to be punished in order to either succumb to or rise above their trauma.
James: A real person. Killed his wife. I think his saying he did it because he "hated her" isn't exactly accurate, but it's enough to be pulled into Silent Hill.
Angela: Another real person. She was abused by her father, and her mother enabled it. She's there because Silent Hill is trying to teach her to recognize the love her "Mama" gave her was twisted and evil; at the end, she still hasn't realized this.
Maria: A projection of Mary via James and not real. Silent Hill offers her to James in the case he wants to continue to believe he truly hated Mary and live out his life with the "perfect" version of her.
Eddie: A real person. Bullied and traumatized for being...Eddie. Took out his anger on animals and at least one person. He's in Silent Hill for a chance to redeem himself, but in the end, Eddie's gonna Eddie.
Laura: She's the one I'm most unsure about. Not a real person? Unless she actually did know Mary from the hospital...Either way, she doesn't seem to be in Silent Hill for the same reasons as the adults. I could see her being a projection of James' worst-case scenario of having the kid he and Mary never did, where she's bratty to the point of possibly getting James killed. But in the end, she un-brats and leaves Silent Hill for the real world with James. Curious what happens to her in the other endings.