Out of all the characters that Sadie Sink could play in the MCU, Firestar makes the most sense for Spider-Man 4. Angel Jones, aka Firestar, first appeared in the 1981 animated series "Spider-Man and His Amazing Friends," where she was the love interest of both Spider-Man and Iceman, also known as Bobby Drake. Introducing Firestar isn't just about giving Peter Parker a new love interest post-No Way Home. She could serve as the first real connection to the X-Men movie in Phase 6, with a potential team-up for "Avengers Doomsday" or "Secret Wars."
However, a more intriguing role for Sadie Sink in Spider-Man 4 would be Hope Summers. Ever since mutants appeared in the MCU, the mystery of the dormant X-gene on Earth 616 has loomed large. Hope Summers could temporarily activate X-genes, paving the way for Earth's mutants to realize their potential. Her character was born through the Phoenix Force's influence, allowing her to manipulate and copy other mutants' abilities. This could make her a pivotal player in Phase 6, justifying an A-lister like Sadie Sink.
Additionally, Sadie Sink playing Edna Brock, aka Madame Venom from Earth 31913, presents a street-level alternative. Madame Venom protects working women with ruthless force when needed. This role could explore what happened to a stranded piece of Venom on Earth 616 and provide Edna Brock with a version of Venom's powers, resonating with street-level NYC. It could be the unique twist Phase 6 needs.
Both roles could elevate Spider-Man 4 and add depth to the MCU, making Sadie Sink an intriguing casting choice. Who else do you envision her playing in Spider-Man's universe?