Background Story
Dream was the codename or project name for Banjo-Kazooie.
The game featured a young boy named Edison which got into trouble into some pirates and Captain Blackeye.
Edison later found a Giant Temple-like building and seeked inside the Temple and later found the The Giant (Now known as Gruntilda)
Banjo - Was going to be a secondary character. Later appeared in his own game.
Edison - The main character for the SNES version. He stirred up trouble with pirates.
Captain Blackeye - The captain of a gang of pirates. Later appeared back in Banjo-Tooie at Jolly Roger's Lagoon. He repeats the words "Once, I had a dream..." which may be a reference to his original role.
Stupid Rabbit Man - First going to be a secondary character in the SNES version. Later changed to the main character when Edison became too "generic"
Tooty/Piccolo - Tooty was going to appear in the game as Banjo's girlfriend but her original name was piccolo to match her instrument. It was later changed for a unknown reason.
Gruntilda/The Giant - Grunty was meant to be a giant in the N64 version. She was later changed.
An idiotic dog - A secondary character.
Tiptup - Was going to be a secondary character, much like Banjo was.
Kazooie - Was not scheduled to appear in any game at all but Banjo still had his backpack to hold items.
 Dream was Canceled
Well... Dream wasn't canceled. It went through a slow process of becoming Banjo-Kazooie. Rareware decided to make Project Dream on the Super Nintendo. But the game took longer than expected, and the Super Nintendo was about to end, so they decided to put the game for the Nintendo 64.
Rareware decided to change to storyline, main character, and everything else. Then it didn't look like Dream anymore, it started to look like Banjo-Kazooie.
 Investigating Dream
Some hackers decided to find Dream's HUB World, Giant's Lair (BETA Grunty's Lair), because Fungus Forest, Mount Fire Eyes, Giant's Lair was said to still be in the game's code.
But all they found was a song titled "Advent":
Advent Theme Song
Some people mistake this song has Fungus Forest's theme song.
In 2006, someone has found a Spanish commercial featuring the Giant's Lair:
Some people mistake that place as Mount Fire Eyes.