There's no 歌う and no Mushu, but the new ムーラン is closer to the original than it may first appear. Check out this side-by-side comparison of the new ムーラン 2020 trailer with the 1998 original.
An animated dramatization of the 1936 musical composition によって Sergei Prokofiev, produced によって Walt Disney, with Sterling Holloway providing the voice of the narrator. It was originally released theatrically in 1946 as a segment in Make Mine Music.