You can find more information and even watch Cinderella II: Dreams Come True on the Internet Archive, a digital library that provides access to a wide range of films, including public domain and Creative Commons-licensed works.
Disney’s current streaming platform, Disney+, offers Cinderella II and III , but with a catch: they are the "remastered" versions. Some fans argue these remasters have overly aggressive digital noise reduction, wiping away the beautiful hand-painted texture of the backgrounds. The colors are brighter, but the soul is slightly smoother.
Thanks to the Internet Archive’s preservation, a reevaluation is underway. Reviews on the Archive’s page for the film are surprisingly warm: