Originally Posted by
John Venus
Movie underwent a lot of rewrites after Wright left but pre-production was done.
I think it's clear when you watch the first Ant-Man that the Janet backstory was tacked on in the last minute, they didn't have an actress cast for the role and her face was always hidden. Hope was initially rumored to be an antagonist but one of the things we heard about the re writes was expanding Evangelline Lilly's role so I think her whole arc about her father holding her back because of the death of her mother and the costume reveal at the end of the movie was something they wrote in later on.
Considering how much time the second Ant-Man spent recapping events from the first movie I think it's clear that the first movie is now skippable on re watch and the only scene you need to watch is the one where Falcon meets Ant-Man.