Leary tells IGN that Spider-Man would have created some kind of formula that brought people back from the dead.
Possibly in 3, there was this idea at one point that Spider-Man would be able to take this formula and regenerate the people in his life that had died. So, there was this discussion that Captain Stacy would come back even bigger in episode 3.
While it could be zombies, possibly the story may have connected to Morbius the Living Vampire in some way?
Marc Webb also recently commented on the Spider-Man reboot offering he would have liked to use The Gentleman and Venom.
Tom Holland will be the new Marvel Spider-Man speculated to first appear in Captain America: Civil War next May, and the Spider-Man reboot follows in 2017 directed by Jon Watts.