When I had Axel (Ally) and Axel (Enemy) duke it out, the codes were sperate, but I imagine you could go both ways. As for the Navigational Map... I have no idea.
EDIT: For some reason the Atlantica Sora code doesn't work in Sora's slot for me... Did I convert wrong? All I'm getting is regular Sora.
That is probably the Riku thats playable, if you look, he's in the stance right before he goes "Sora" and raises his blade in the mini cutscene when Sora gets captured by Xemnas. Either thats a decoy, and SquareEnix knew we would be looking for him or they made him fool-proof and thats as close as we're gonna get. I do hope it's a decoy, or like a beta test that was left in.
I never thought that Squall would do a lot of damage to Sephiroth... But once he charged up the big gunblade, he was doing the amount my finishers would normally do!
Interesting... When I was fighting Xigbar on the Black Pearl's deck, I fell through the floor. But underneath it was solid floor that you could walk on, even though it is unaccesible by normal means. Of course, if you walk on the water you sink.
But it fixes itself when Xigbar "changes" the scenery, you are warped back onto the glitchy solid floor again. ^^;
EDIT: Also, I used the Dual Wield Roxas code, but it gives him Sora's voice.