Boy, did I have to dig into my archives for this one! I'm going on my notes from the time; it would be interesting to see a videotape of it now 11 years later to see if my opinions would have been any different.
Chen & Sato were both pretty good, BUT they were, respectively, 5th & 6th after the SP, so even had they won the free skate they likely wouldn't have won the overall title anyway.
So for me it would have to come down to Bauil or Bonaly, which for me is a tough choice. I could never understand how Bonaly could have been given 5 European titles when she never really knew how to actually skate, and I've never been much of a Bauil fan, either; she IMO always had the "OOOOOOOOh, isn't she precious?" routine going on a little too much for me.
But, given the overall circumstances of that wild night in Prague, I'd probably give it to Bonaly. My notes indicate that this was actually one of the rare occasions where she put on a program that was actually moderately championship-level and she had IMO actually improved quite a bit at that time, tho in later seasons she fell right back into her old mode again. Bauil I considered over-rated, tho I did make a note of her "above average on-ice personality".
What I would have liked to have seen happen was Josee Chouinard rising to the occasion; she was the final skater of the night and was definitely in position to win, but unfortunately she had way too many problems to even maintain her 4th-place SP position.