Paul Feig has thrown a few names including Lizzy Caplan, Jennifer Lawrence, Melissa McCarthy, Emma Stone, Gillian Anderson and other names such as Channing Tatum. Lizzy Caplan can play the female Venkman. Of course, they are going to be more creative than that. There is a chance that some of the old Ghostbusters such as Dan Aykroid and Ernie Reyes Jr can do a cameo.
While there are accusations that this could be a gimmick to give the franchise a greater appeal, Paul Feig has expressed enjoyment in working with funny female actors. Feig has also directed feature films with female leads that have proven to be successful.