I have added Fantasia and Fantasia 2000 to my Plex library they both showed up initially, but when I added them to my Disney collection Fantasia 2000 disappeared completely. Yes I have hide films, but they usually show in the collection this one is not.
Another question I have is something like Disney’s shorts such as Steamboat Willie do they have to be made as an individual movie or added to a movie title with shorts in the name. Alternatively could they be put in a collection such as Disney Shorts with no movie in it. Just the shorts.
Inspect the plex media info of Fantasia. see if it additonally mentions the file name of Fantasia 2000. If it does, the two movies mere merged into one item.
To avoid such incidents, stick to the Plex guides https://support.plex.tv/articles/categories/your-media/ for naming and organizing your media files.
Some of the shorts are listed as movies on TheMovieDB.org. So you can add them just like any other movie, but they will also appear as regualr movies in Plex.
A different method would be to treat them as episodes of a TV show.
See https://thetvdb.com/series/disney-animated-shorts for a reference to which short is which season and episode number.
You will have to rename your files and organize them into a folder structure as is required for tv shows in Plex for this to work.
For this approach, you will be needing a library of the type “TV shows”.