I dunno what happened to Thalia, she just left apparently, and SparkleRose, (I know this because I keep checking when her last activity was on her account) I think took some time off because of a family tragedy if something. Though the last time she was one was when he commented on something unrelated to that, so idk.
I've never met Reader before so I can't tell you.
GEMHeart prob left because she became an adult.
Hope I helped a little!
-Nobi
