1.
The Movie filter in the Types tool checks for a known Movie match in the filename
(e.g. Avatar 2009) and does not further limit this to video files. Further restricting this to video files that are also movie matches would be easy, and that change could be made if you make a case for it.

One of the Movie items is a folder, which likely contains many files, leading to a higher file count.

Requiring movie / episode items to be video files make sense to me. In your particular case, that would result there not being a movie category at all though, since all folders / non-video files would be excluded.
2.
Any video file could be a movie file really, but FileBot does not further check or cross-reference online every single file name. There's also no special logic to exclude "video files that are extras" from other "video files" and adding something like that makes less sense to me, since video files are video files.