In act two, what kind of influence does Abigail have, though she does not physically appear?
By act two, Abigail's influence over the proceedings has already begun to snowball. She started everything off with her initial accusations of witchcraft, and a hysteria has developed. By act two, all of Salem is suspicious of witchcraft wherever they look, which is why people like Elizabeth Proctor and Rebecca Nurse are "mentioned" in the witchcraft proceedings.
I know not if you are aware, but your wife’s name is - mentioned in the court.
That is the power of Abigail Williams. She doesn't even need to accuse anybody; she simply needs to somewhat mention a name, and the court is obligated to pursue that person as already guilty. The worst part of the entire thing is that no amount of proof offered by the accused can prove their innocence. The only thing someone like Rebecca Nurse could do to save their life is to confess. For Rebecca, that is not an option, because she knows it is a lie. The double standard of this situation smacks readers in the face, because Abigail also cannot offer up any kind of proof. But that doesn't matter, because of the fear of witchcraft that she has already created.