Well, I'm now halfway through chapter 6 of the prologue again, only this time I'm on the harem route. I gotta say, I really missed a lot of stuff by pursuing only Sky during my first playthrough. I'll give a proper review of this game once I've completed it on the harem path.
There are still some scenes and special images I haven't unlocked yet, and I'm guessing that some content in this game can only be unlocked by pursuing specific solo routes, which I'm fine with! I'm playing the harem route first though, because it's the canon route, and I like canon. :)