I still think that the announced cast is for the festival, not the movie. The additional cast is listed on the festival's website
, which means they'll appear there. If the cast was for the movie, then they'd update the cast page
of the official site. For example we know that Armstrong will also be in the movie, but his VA isn't on the list of the festival's page. So I think Amber misunderstood the announcement.
: Here's what the Twitter page says: