For people waiting for Eve to turn into the older form we see at the beginning, it likely won't happen. Author's said multiple times in response to people asking that they don't see him fitting into the main story so they'll only doodle that form from time to time for their twitter.
Me personally I used to watch a lot of old anime so Eve kind of just looks like a girl lol, at least in anime art style standards
Really recommend the movie. It takes some bits from here and organises them into a nice story following the characters as a group of delinquent "friends". I think the movie also made a much more compelling character out of Kujo by giving an arc to his ex-friend Aoki, which ended up fleshing them out through an interesting conflict. Also just a beautiful looking movie in general, very talented director.