There is evidence suggesting that Pikachu in this game is actually Pichu from Super Smash Bros. Melee, albeit evolved:

• Pikachu in Brawl uses Pichu's wall jump ability from Melee.
• Pikachu's Final Smash in Brawl is Volt Tackle, which, in the Pokemon games, can only be inherited by an egg-born Pichu.
• Pikachu's blue costume in Brawl uses the goggles worn by Pichu's blue costume in Melee.

Pit was first depicted with blue eyes and a laurel crown in promotional artwork for Kid Icarus: Of Myths and Monsters, which was not released in Japan until 2012. If the eye color and crown of Pit's design in 2008's Super Smash Bros. Brawl was influenced by Of Myths and Monsters and wasn't simply a coincidence, that would make it the first and so far only instance of Super Smash Bros. referencing content from a game without any kind of Japanese release at the time within gameplay, and shared with a sticker originating from Of Myths and Monsters as the first representation of a game without a Japanese release whatsoever outside of the Chronicle (which is also technically tied with trophies in the same game from Elite Beat Agents, a heavily modified localization of Osu! Tatakae! Ouendan).