Max Dillon is the head of a team hired by Norman for some secret project. It just happens to involve working with power lines. Circuitry for some big project. A rival to OsCorp has some hired guns sabotage the project, creating Electro in the process.
Electro, as a survivor, could be a liability to Norman. So he hires Allistair Smythe to design bluprints for the Spider-Slayers. To prevent the Slayers from being traced back to OsCorp, he has the international spymaster, Chameleon, stealing resources from OsCorp's competitors to design the Spider-Slayers.
Meanwhile on Peter's side of things he might be trying to busy himself with a career to keep himself from breaking his promise to Captain Stacey. Suspecting OsCorp's involvement with his parent's disappearance, Peter persues a job with OsCorp and a side job as a freelance photographer.
In his mind, Peter would be in a position to investigate OsCorp while working his way up in the Daily Bugle. This way, he could expose OsCorp's possible illicit activities to the world. Of course, he would still be tempted to continue his relationship with Gwen.
Eddie Brock could be introduced as an idealistic photographer who is also interested in getting a position with the Daily Bugle. He and Peter might hit it off at first before they're thrust into competition with one another.
In the aftermath of the proto Spider-Slayers and Electro, Norman sees a chance to tighten his grip on the city by taking the underworld, which could be the plot for part 3.
In Part 3, I see Peter and Eddie becoming more competitive in their freelance work for the Bugle. Eddie could be given some inner demons dealing with his past employment, where he was fired for faking some saucy pics.
Desperation drives Norman Osborn to don the mantle of the Green Goblin to ruin his competitors and restore OsCorp's public image. To that end he launches clandestine attacks against the OsCorp's remaining rival corporations, lifting their gear and leaking it to figures in New York's underworld.
Among his stooges are Herman Shultz, who gets the Shocker outfit/gauntlets. With other B/C-list rogues, the Goblin is able to drive a wedge into the underworld, initiating a city-wide spree of gangland violence. The warring mobsters could be individuals such as Tombstone and Silvermane, for example. He assigns Chameleon the task of implicating Spider-Man in the recent Electro/proto Spider-Slayer rampage (TASM 2). We learn that Chameleon was promised a serum to help his ailing brother, Sergei, in exchange for his services to Osborn.
Meanwhile Norman prompts Allistair Smythe to update the proto Spider-Slayers, then offers the mechs to the NYPD to help them deal with the gangland violence and Spider-Man.
The damages from the showdown between Spider-Man, the proto Spider-Slayers, and Electro would have led the NYPD to reconsider their relationship with Spider-Man.
Peter would be left to deal with the mob wars, as well as the Goblin and his right-hand assassin, the Chameleon.
I'm thinking of tying Peter's parents in with the Symbiote's creation. This idea for a Part 2 and 3 provides a conclusion while leaving open a Kraven's Last Hunt scenario with the symbiote.