That could work, but most WTs done by devs are... let's say oversimplified. You know the other popular VN's, they're basically the "green choice is best" kind of thing and not truly that helpful (imho). I just looked and haven't messed with this particular VN since v0.5.5 so I'll take a look after I finish the other project I was planning on releasing today/tomorrow. I've pushed two things off my plate already this morning and that would be the third. Surely there might be enough room on it to at least allow me to eyeball what we have going on. We'll see.
You know what I wish, especially for a game like this? If a walkthrough (whether a mod or pdf) would just lay out the choices for a certain path or paths that exist in the game. Even the pdf in OP is just a flow chart but it's still confusing as fuck because it's all one giant flow chart instead of having things separated. If it was on a mod, I wish I could just have a setting where I click a button that says something like "Layla only" and the WT would adjust to only show green for choices that were good for that path and then do Blue for Choices that don't affect it and red for choices that end relationships or cause negatives. I get that it'd be a lot of coding and such but with a game this confusing for pathing, it's getting hard to know.
Like there's Val content in this one I don't see, mainly because I think I'm with Layla. If I were on the Friends with Layla path instead, I'd probably see it but I have no idea if that's true or not and I don't want to spend an hour fast forwarding through the entire game just to see if I was right.
If you play "Where the Heart Is", CheekyGimp and Ace built a system that literally lets you choose what chapter to start on and what paths you're on with the various girls. That needs to be more common.
No, his mother isn't a love interest. There are certain options but they don't lead to anything, same for Melissa.
I don't know if she's doing it to purposefully troll the incest crowd but I do know she has her reason for doing it whether that's for story reaction or trolling I don't know.
I do know that his mother is not and will never be a love interest.
As for Melissa, I don't know if she'll ever get any actual scenes but i'm 99% sure she won't.
I think the Emily Love points will affect the ending. More or less about how good your relationship is with her in any given epilogue. I also am of the belief that the Melissa stuff is just for sexiness and laughs because #1 there's no way she'd act on it and #2 she'd never do ruin her relationship with Emily or Erynn for some sex with a younger man. It's just a fantasy. Which is just like reality, which I like. Women and men can have plenty of fantasies, but unlike VN's they don't just instantly act on them.
As for the Kiss and the Sexy in this episode, that's clearly just for fun, and a call back to other things that have gone on. The only important choice as far as points go for Emily is encouraging her to go on the date with John. Yes that's right, Nyx is making NTR the correct choice to stick it to the incest crowd.