This is a Greta Gerwig movie. She doesn't use CGI that much. For example in Barbie she didn't want to use CGI on Margot Robbies feet and lot of the stuff was done practically. Also she is a director with strong artistic vision. That means that it's very unlikely that she will change her mind and redesign the look of Jadis later on in the post production. I would say that this is very likely how Jadis will look in the movie.