I am so glad this became an actual thing. I wonder where the 4th sister is? Hopefully writing some yuri stories...
I remember someone saying that one of the sisters in Yuri Family made a cameo in Met My Sister on a Dating Site, so (if that's not one of the girls here, I don't remember what she looks like at all), perhaps she moved elsewhere or something?
More mochi is always good. I also hope that it will be Kasumi's mom. We could use some older Mochiverse couples.
On a side note (Might not be the right place to post this since the chart doesn't have new info from this chapter): I found the missing link between the "More than friends" section and everything else! The Video Rental Store customer is (likely) one of Kasumi's friends in the last chapter of More Than Friends.
Here's the (Minor) revision: https://i.imgur.com/zAh6Mom.png (I ran out of conspiracy board pictures)