Thanks for the tl;dr (and for complimenting my cute elf wife). I re-downloaded the first game just to see what else was there with regards to the plot. This and the prequel were pretty much identical in terms of plot except that the main antagonist this time around was the teenager version of the previous one (he was a child in the first game) and instead of seeing a doll version of Katagiris' brother, which was the case in the first game, you get to see the actual flesh-and-blood brother so this time there really is actual incest...in the dream world at least. Not complaining that they're similar though, I still enjoyed going through the game.
With regards to the sex scenes (penetrative), the guy who said that there were more FMCxOP sex scenes technically wasn't wrong since in the first game the MC only fucked Katagiri once in the ending (if you exclude that one particular H scene wherein MC fantasized fucking Katagiri), but this time around they fucked twice (in the hypnosis room and in the ending) so, it really is close to 90% lol.
Though, in terms of overall H scenes, this and the previous game were roughly on par. The first game roughly had around ~15 H scenes with you and ~8 H scenes with others, while this game had ~20 H scenes with you and around ~3 with others. Just a rough number, because the line whether it's an H scene with the MC/others is pretty blurry. Honestly, I prefer the H scenes in the first game, but the ones here are still pretty good. I feel like the first game had more titty shots of Katagiri than this game.