Path D is of in Day 2 you decide to don't open up eventually with Jack
Mostly there is some change in dialogue during it's course, it's mostly Raymond and Jack's time blushing or being overly friendly being toned down, it's more clearly in Act 4 what truly changes, so feel free to use the Chapter select to get there of you want to play the new content
And I can't really say much on the theorizing part so... yeah, definitly will have more clues as the chapter continues
And thanks for sharing your thoughts! I love hearing opinions and theory/guesses on the story