About the pastebin: I'm hardly an expert on Japanese copyright law, but my understanding is that it doesn't recognize the possibility of selling IP. Instead things work so that the rights are rented/leased/whatever the correct legalese here is. Commissions and such don't count of course, because the ownership is determined in the contract. Hence the character Hosimati Suisei belongs to her because there's no way for her to give it up even if she wanted to, but her redesign might belong to Cover. On the other hand as a standard practice Japanese companies make contracts that have penalties so severe for unilateral retractions that backing out would be a financial suicide, although for those who like to pay indemnities from their pension just for the sake of saying "fuck you" it remains a possibility. And as
>>6382658 noted, Cover owned IPs are publicly available and Hosimati Suisei is not one of them. Even if I've misunderstood everything, I don't see what other party could have ended up with the copyright. I wish someone whose reps allow them to actually decipher legal writings could set this one straight, but I doubt there is anyone here.
Also, while the Project Winter stream was indeed where the psychopath meme was born, she always had an edgy streak and was called yankee (that is, delinquent) idol back in the day.