Well with Curt Connors back for SM4 (You are not allowed to view links.
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For Black Cat, and this is probably the worst thing I'll ever say, they really do need to get a cheesecake actress. I love the character and the interplay she has with Spider-Man in the books, but I think to bring her into the movie world they really need a sort of bombshell actress. Then again, this franchise has made a history of casting odd, controversial choices (Tobey as Spider-Man, Topher as Venom) so maybe they could go with a Julia Stiles (or someone else) Black Cat.
Other options for the little red-haired kid: Normie? I don't know how far in the future they're putting this, but Harry is as old as Peter, so if people can speculate about Peter and MJ having a kid, why not Harry having little Normie?
If there is a Black Cat or Lizard in this movie, then I hope Hasbro steps up the SHS offerings. I think it was such a disappointment that with Gambit, Deadpool and Sabretooth all being sort of bigshots in XOW, Hasbro made movie versions of Deadpool and Sabretooth, and some half-assed repaints of the comic versions. I was so expecting a new Gambit sculpt.