With the exceptions of King Louie the Orangutan, Winifred the Elephant (Colonel Hathi's mate), and the wolf pack, all the characters from The Jungle Book (1967) return in this sequel. The character of King Louie was cut because Disney would have had to pay the estate of voice actor Louis Prima had the character appeared in the film in any form.
When Shanti goes to get water for the first time, and Mowgli and Ranjan sneak out to follow her, she seems to be humming the song that first lured Mowgli into the village in the first place in The Jungle Book (1967), "My Own Home".
John Rhys-Davies the voice of Mowgli and Ranjan's father use to voice Man Ray in SpongeBob SquarePants (1999). In the fifth season of that show Bob Joles the voice of Bagheera replaced Davies as Man Ray for the rest of that show's run.
The trivia item below may give away important plot points.
A plan for "The Jungle Book 3" involved Baloo and Shere Khan being captured and sold off to a circus in Russia. So Mowgli, Shanti, Ranjan and Bagheera would have to save them, and Shere Khan would have changed his ways because of his capture. Corey Burton would've replaced Tony Jay as the voice of Shere Khan. But after John Lasseter became both CEO of Disney and Pixar and due to the film's lacklustre box office returns, the idea along with ideas for a number of other disney sequels were scrapped.