Pocket IGN has a report that says Sonic Advance for GBA will work with the GameCube version of Sonic Adventure 2.Sega has announced in Japan that it will incorporate GameCube connectivity into the Game Boy Advance action adventure, Sonic Advance.
Like the Dreamcast version of Sonic Adventure 2, the GameCube game will have a hidden minigame, the Chaos Races. The Dreamcast version allowed for raising of Chao creatures through the use of the system’s portable VMU memory cards. But in order to take advantage of this feature on the system, you must raise Chaos creatures on the Game Boy Advance, through Sonic Advance‘s minigame, Chaos Garden Advance. They can be transferred to the GameCube through the use of the Game Boy Advance/GameCube communication cable, set to release sometime after the launch of the system in Japan.
Hopefully, the Game Boy Advance Chao minigames will be a bit more elaborate than what was offered on the VMU/Dreamcast versions.
— Craig Harris
Source: Pocket IGN