So apparently BC keeps that information to himself, but I did get a few names when I asked a year ago. There's not all definitely gone, but the speculation at the time suggested things weren't looking good for these ones.
- Reiya, Sloth Chan's sister
- Akina, the neko who is into Metal
- Alice, the cock blocking brat
- Ilyia, the geisha looking Russian chick
- Arisa, the red head who worked out with Mao that one time
- Hobogirl, the girl, who is also a hobo
Alice got picked up by Skummy a couple of months ago, I believe. So, she seems to be back thanks to fan demand.
The others may have had their circumstances change, but I couldn't say for sure.
Reiya and Arisa getting dropped sucks because they both had connections to established characters. Reiya is Sloth-Chan's sister, and Arisa is Nanami's cousin, I think. It feels like a waste to drop those two specifically, when that could have led to interesting stories down the line. As I noted, she also had a workout session with Mao and Matsu, and it would have been nice to see the two of them become friends or rivals.
Ilyia also has one of the more unique designs, so it's a shame that won't get put to use.
I think Sunari, Migoto and Michiko, Kasumi, Hanabi, and Emilia are all safe. At least they were a year ago. After how big a delay this has been, I wouldn't be surprised to see a few more casualties along the way. I think I've seen most of there creators being quite active in the Discord, so if they aren't supporting now, they probably will once things pick up again.
Personally, I think they should have gutted the T8s while they worked on the merge, and just used them for the T8 spinoff game that's expected to happen once EC gets it's momentum back. Replace any characters that are worth keeping around, or are part of vital scenes with "Suspiciously Similar Substitutes". Too late for that now of course, but a man can dream.