Basically, Project Pegasus steals the Serpent Crown from them and they battle the Fantastic Four in hopes of getting it back. Anaconda does virtually nothing other than talk in a southern accent, so she might not have the same powers as she does in the regular universe. Black Mamba claims to not feel any pain, so the Thing merely tosses her away from him. Apparently, her real name is Janis, since Asp shrieks the name out when Black Mamba's thrown. Asp isn't shown with any powers, and Death Adder is pretty much just a feral woman. It strikes me as odd that they'd alter Death Adder's gender instead of just using one of the other Serpent women, such as Fer-de-Lance or Coachwhip. Either way, she gets defeated by Invisible Woman while Anaconda gets beaten by Mr. Fantastic.
Princess Python is pretty much the only one with major powers. She first grabbed one of Human Torch's fireballs and then threw it back at Mr. Fantastic. She also had super-strength, since she knocked the Thing around and eventually took off a piece of his rocky skin. Makes me wonder why she's carrying her snake around with her, if that's the case. After they're defeated, the Thing calls them freaks and Black Mamba freaks out, screaming that he is the freak and that he will die alone. That begins the crossover of Ultimate Power, as Mr. Fantastic inevitably tries to find a cure for Ben's transformation. I'd like for the Serpent Squad to return, but only if they're not written as such awful villains. Their dialogue was seriously horrendous, and I can only hope the next writer who uses them will redeem them.
They also had an entry in one of the Ultimate handbooks, but nothing beyond what was already seen in Ultimate Power was in it.