I know this has been discussed, but I actually have proof that she is in the game. I recently bought "All About SNK 1985-2000" book published in Jpn. In the section for Wild Ambition, they have Xiang-Fei screenshots and they also explain how to get her, but it is of course in Jpn. I'll scan the pictures and text and uploaded so people here could see and figure out when I get back from my vacation.