Over the course of the years, Disneytoon Studios has made direct-to-video and occasional theatrical sequels to many Disney classics. When compared to the originals, these sequels were often panned by the critics for its poorly written plot and bad animation.
Although I like some of these sequels, many of them don't have even half the magic and heart that made its predecessors so special. Disney simply pretends that these films never existed, the promotional material in many instances contradicts what is shown in them and many times they weren't even made by the original team, so I ask the question, are these sequels even canon?
To be fair, the promotional material for the even the Animated Classics at times contradict what is shown in them (case in point, the trailers for Beauty and the Beast made it sound as though Gaston was fully aware of the curse befalling Beast and his servants with the line "one man who wants to keep the spell alive" in reference to him, and yet in the actual movie, there's very little suggesting that Gaston was even AWARE of the Beast formerly being human, let alone there being a curse.).
And as far as whether they're canon, some are canon, some are not. That's all I can say on the matter. The ones I can probably say are canon are the Aladdin sequels (since Iago's reform has been consistently shown in various extension media, and aside from that, Return of Jafar acted as a backdoor pilot to the TV series), Simba's Pride (thanks to Kiara and Kovu appearing in The Lion Guard), and probably Return to the Sea (since at least one book showed the wall that trapped a dolphin, implying that it was canon.). Probably also Cinderella, for the same reason why the Aladdin sequels are canon.
Likewise, the ones I'd probably argue aren't canon are Pocahontas II (since marketing still has John Smith being Pocahontas's beau), Ariel's Beginning (since it contradicted pretty key stuff from the original movie, let alone the TV series which Musker and Clements oversaw), and probably also Fox and the Hound 2 (there simply wasn't any time for that movie).
Beauty and the Beast's extension media is in the gray area, especially when even the original movie had some continuity problems with itself.