Santa was kind enough to bring my daughter Karaoke Revolution, and we've been having a ball with it. But, the microphone looks like it belongs to a 70's cassette recorder. (It's the same style as the Mario Party mics, just black.)
I saw that Konami made a pretty nice looking mic for the PS2, but after Googling the crap out of it I couldn't come up with anything else for the Gamecube.
1) I muttered 'What am I doing?' many times during the 3ish hours the game lasts. The only onscreen text explaining what's going on is early on, when you're told to hit O (circle) to perform an action. You know you're heading (journeying!)