Mo Sets It Straight

Both Asuka and Xiaoyu have schoolgirl uniforms in console version.

In arcade mode, however, Asuka only has the standard 1P and 2P costumes and Xiaoyu's schoolgirl outfit is accessed by pressing Start to select her. But this is arcade only, I think.

In the console version, you need to purchase Asuka's secret costume for 500,000 to get her schoolgirl costume. Use Triangle to select Asuka to have her fight in it. Circle will get you the geisha costume. Effectively, you're getting two for the price of one. For Xiaoyu, buying the extra costume will get you the black and white skimpy panda costume. To get the schoolgirl outfit, you just need to select her with a shoulder button. I'm not sure if you need to buy the secret costume first (getting two for one like Asuka) or whether the schoolgirl is just there to begin with.