I doubt that they're both scum and I doubt that Creeper has some confirmation of Clayface. However, what are the odds that they decide to copy Deadshot and use his action on Calendar Man, but Clayface instead kills Riddler while Deadshot kills their original target (Calendar Man)? That is way too much of a coincidence, and I don't believe in coincidences.
Face it Crane, Deadshot is the scum day-killer. You and Music Meister are standing around saying that it isn't 'strong enough' evidence against Deadshot, when frankly, there isn't much anyone can do but claim things. If someone came forward with an investigation result, would you dismiss them saying that it was 'only a claim'? No, you would follow the investigator's result just like everybody else would, and if it turned out wrong, then you would start entertaining possibilities that the investigator lied.
Nope, I didn't forget, and I'm not 'happy to forget' it either. In fact, I think it's very likely that the scum will convert Creeper at some point. However, he isn't converted at the moment. The scum can kill or convert during a day/night phase. They killed today (and don't say that a day-kill doesn't count as a kill. It does.), so he wasn't converted on Night 2. He wasn't converted Night 1, either, because since Day 2 he's been on Ventriloquist's case, who almost everyone (including you!) agrees is incredibly scummy. If you think that Creeper has been converted, then you can't suspect Ventriloquist. Use your head!
I don't know, but it's pretty easy to figure out. If Clayface is scum, why would he use someone else's action on Nygma? Why wouldn't he just use a collective kill? And don't come to me saying the scum don't have a killer. Every scum team has a collective kill (except in a book called Prison Riot, but that was because there were four scum teams).