I had the same problem with the videos. I've also been unable to play any ADX audio files as they all seem garbled with lots of extra noise. It seems like they've changed the format (or encryption) of the files.
Kentilan, have you had success with the ADX audio files?
Not really. I can hear the music but there's a lot of noise over it.
Kentilan, great work with the model viewer so far, shame most of the character models look crap without rigging/animation offsets. I don't blame you if you don't want to code that far, sounds like a computational nightmare. I'm pretty sure that SEGA used rigs and applied mocap data to them. With some strange jerkiness to them in an attempt to make the movements seem more "real" but they seem to go overboard with it, I noticed this in PSU and now NiGHTS. (I have to admit I'm curious if this is in the animation data or coded into the games)
Yeah, this stuff seems too complicated for me, and I've never dealt with rigging before. Though I'd like to give it a try later.
Owl reveals himself for the total Spaz he is...

Are you sure it's Owl? That's strange, I don't remember anything like that in the game...
Trouble is, I can't play these files properly. I tried using vgmstream as you suggested, but I can't make it work. The executable tells me it can't open the files, and the Winamp plugin stays silent