the last girl showed up for me.
i just played normaly and got her.
no idea what the trigger for it is tho.
Weird. Beats me. Maybe I'm missing something due to the admittedly less than stellar translation. Machine translated maybe? Doesn't matter.
Well, I restarted and got all the rooms to show up/fill up. Then I beat the game, maybe by accident. Seems like the last girl (room 6) may not show up on a set timeline, she only triggered after I got the wife (room 3) to get to 3 hearts by using all the drug possibilities. Again, I chalk up the majority of the issues to poor translation.
For anyone having problems triggering the single mom (room 5) to do the nasty at night, you apparently have to have gotten her top hearts to level 3. This requires using both kinds of drugs. So if you haven't unlocked the sleep drug yet, I'm pretty sure it's impossible to finish the single mom part (that happened last for me).
As for finishing room 6, you literally have to sex her for an entire day, takes a few minutes since can only go x2 speed, skipping doesn't seem to work during sex... at least to finish room 4 you only have to sex her for a few hours during when she cams.
But seriously, translation leaves much to be desired... also would be nice if gallery scenes included text/scene, not just the image, but oh well!
Edit: PS, also pretty sure that to finish room 6, you probably need all 5 energy (unclear if necessary to do most or all of positions, dunno if switching it up is necessary).