There's a good chance that Genos will come out I think because he is a result of Square and Nintendo. It is really fitting.That's why this Square character is going to be very interesting no matter who it is.
Geno: Only really known to diehard Smash fans.
Erdrick: Virtually unknown outside of Japan (although the name "Dragon Quest" is fairly well known), licensing issues.
Sephiroth: Would be the first unique secondary addition to a third party IP, and would be getting in despite an absolute dearth of FF content.
Crono: Dead franchise that Square has seemingly no interest in returning to.
All of the above is why I'm still skeptical about the Square character actually existing. Every choice seems like it has a drawback.