Wow, ok I might get killed for this but I think I just solved this thing.
Name Claims
Abel -
Blanka - Fufinu
Evil Ryu -
Guile -
Guy - GoW3ever
Makoto - Gnizmo
Seth -
The only people that have not name claimed are Hephaestos , silver-tiger, Vetteman and Snake-Eyez. I am Guile and I have been proved innocent (see above) so that leaves 3 people left. This means that Abel, Seth and Evil Ryu have yet to be claimed. I highly doubt that Mafia B would have only 2 characters in it (So far only Juri is in Mafia B) so I believe that out of the 3 characters left to be claimed, there are 2 Mafia B and 1 serial killer.
The serial killer is OBVIOUSLY Evil Ryu (based off of character roles which have been right so far) which leaves Abel and Seth left to be in Mafia B. In Super SF4, Juri (Mafia B) starts to work for Seth so that ties him with Juri. Abel lost his memories and if I recall had some ties with Seth, which links him with Juri.Out of Haphaestos, Silver Tiger and Vetteman, I think Silver Tiger is telling the truth about being Abel, but not about his affiliation. He couldn't claim he was somebody else as whoever he claimed, somebody else would claim him too, making him look suspicious. His only option was to claim his character, but lie about where he stands.
I believe that Vetteman is Evil Ryu and is the serial killer. Which leaves Hephaestos left as Seth. I know that this seems like alot of assumptions and all that, but that's the way I see it, and I have a feeling that I'm right. If there's a doctor in the house, please protect me as I will most likely die tonight.