Changing avatar to avatar-movie makes sense to me.
However, I think repurposing avatar to be something other than a reference to the movie is a bad idea.
First and foremost, the term "avatar" does not exclusively refer to "virtual-representations of real people".
The older meaning of the term refers to physical manifestations of divine beings. This term is used in this fashion by at least a few titles that would fall under this site's scope, and would cause confusion with "avatar" as used in the more technological/virtual sense.
The two concepts are far enough apart that I don't think it makes sense to lump them together under a single tag.
Even if they were closer in concept, I don't think "avatar" is universally accepted enough for everyone to assume that a virtual representation of a real person would be tagged "avatar". I have seen holo presence, tele presence and remote viewing/presence used to describe similar concepts, and I've also seen the concept used in sources that never attempted to label it one way or another.
This makes the tag insufficiently useful, imo. If not everyone is going to assume that that's the term they should be tagging/searching upon, it isn't worth creating a tag for it.