We realize there is a lot of controversy surrounding the success of these books because of the author’s unusual path to publication. It originated as a Twilight fanfiction and there are several direct comparisons (mostly the built-in character infrastructure) that can be made between the two stories. But as with any movie adaptation, several changes could be made to the characters and/or setting. So perhaps in developing the script, some of those comparisons to Twilight will be changed to lessen any similarities.
Even as Twilight fans who originally found our way to E.L. James’ story via fanfic, we remain Fifty Shades of Neutral. The question of possible copyright infringement is something that the authors, publishers, and their lawyers will have to work out. If anyone lawfully decides to halt production of this story becoming a movie, then we will observe such a ruling.
I think what we would all love is for Stephenie Meyer herself to release a statement about how she feels about the issue.
The bottom line? We are fans of both series, separately, (there’s no Team Twilight versus Team Fifty Shades here) and we will continue to be fans of both.