Right now, Adam Scott is supposedly portraying good ole Uncle—well, pre-uncle—Ben Parker. He was recently spotted on set filming a scene with Dakota Johnson wearing matching paramedic outfits, though this doesn't confirm whether that's the character he'll actually be playing.
Emma Roberts could potentially be Mary Parker, Peter Parker's biological mother whom we never got a chance to meet in any of the films.
As with much of Marvel lore, there are usually a few different iterations of specific characters, and it's no different when it comes to Madame Web. Currently, it's being rumored that Sweeney will actually be portraying the other Madame Web, Julia Carpenter. However, Julia Carpenter has also gone by the alias of Spider-Woman, so it's unclear which of the two she'll actually be portraying if either at all.
Celeste O'Connor is rumored to be playing Mattie Franklin, another character who goes by the name of Spider-Woman.
There are a few rumors swirling around about where Mike Epps' character will land, but the theory that's getting the most chatter right now is that he'll be playing Mattie Franklin's father, Jerry Franklin.
Currently, Isabela Merced is rumored to be portraying Anya Corazon, though it's more so just a fan-fueled idea at the moment—nothing has officially been confirmed by Marvel.
Tahar Rahim's character is still being kept pretty tightly under wraps, though some fans are guessing that he could be playing Ezekiel Sims.
Zosia Mamet is the newest to join the cast of Madame Web, and since she was just recently added, her role is completely unknown as of right now.