At one point, did Spider-Man: Far From Home have a different post-credits scene? In Jon Watts' 2017 film, Spider-Man: Homecoming, Michael Keaton's Adrian Toomes, aka Vulture, returns in the post-credits scene and is briefly confronted by Michael Mando's Mac Gargan, aka Scorpion, who wants to know what Spider-Man's secret identity really is. While Vulture doesn't divulge Peter Parker's name, the scene was meant to imply the seemingly inevitable introduction of the Sinister Six team. But that still hasn't happened yet.
When it came time to start pre-production on the sequel, Spider-Man: Far From Home, it was widely reported that Keaton would reprise his role as Vulture alongside Jake Gyllenhaal appearing as the main villain Mysterio. This continued to tease the Marvel Cinematic Universe's set up for the Sinister Six - a supervillain team comprised of Spider-Man's most dangerous enemies, including the aforementioned Vulture, Scorpion, and Mysterio, as well as Electro, Doctor Octopus, and even Kraven the Hunter. But the thing is, Keaton didn't come back for Spider-Man: Far From Home.
Given what was reported prior to the start of production and the somewhat clear set up for the Sinister Six in Spider-Man: Far From Home, is it possible that there was actually another Spider-Man: Far From Home post-credits scene? Unlikely. On the set of Spider-Man: Far From Home, producer Eric Carroll confirmed to Screen Rant that Keaton definitely wasn't in the film and that they weren't going to include any explicit references to the Sinister Six, which is technically true to the final product.
While sometimes Marvel Studios tends to redo their post-credits scenes or have them filmed at the last minute to set up a future movie (such as Samuel L. Jackson and Cobie Smulders filming their Avengers: Infinity War credits scene around the time Avengers: Endgame and Captain Marvel were shooting), that isn't the case for Spider-Man: Far From Home. In fact, the first set photos that had appeared online, as well as the trailers for the movie, include parts of the post-credits scene.
So it's clear that having Peter Parker fly around with MJ and then having his identity revealed by Mysterio and J.K. Simmons' J. Jonah Jameson was always the plan. Even if there was an idea of having a Sinister Six set up by having Vulture and Scorpion (or just Vulture) reappear with Mysterio at some point in the planning stages, it never made it through pre-production. However, that doesn't mean it's not something that could potentially happen in the future.
Mysterio can still return in the MCU alongside Vulture, and together they could form the Sinister Six to give Spider-Man his greatest threat yet. Furthermore, the idea that Norman Osborn's Oscorp potentially buying the old Avengers tower seemed to have been spawned out of pure rumors and fan excitement, which tends to happen quite often with comic book movies. Unfortunately, that doesn't mean there was any real truth to it.