The Tales of VS. official site has been updated with its sixth system video, showing the game's "Correspondence Battle", or the multiplayer mode.
"?????" as "Communication Battle", but we'll stick with Namdai's own translation.
Using the PSP's Ad Hoc mode, you can fight against your friends in a multiplayer battle. You can set up a "rule" for each battle, such as "___ Panic" (can't make out), "Gel/Gummi ____" (also can't make out, sorry) "1-Life Match", and "Point Battle". I'm not sure about Panic and the Gummi, but 1-Life Match is last one standing battle. In Point Battle, the player with the most points (as shown in the numbers just above a character's face portrait) wins. You earn a point for a kill, and lose a point if you get K.O.'ed by another character.
Before a match starts, you can set the Rule (the ones mentioned above), the Stage (battle arena), the Time limit (1 minute, 2 minutes, etc.), the Item, a Custom (currently not highlighted, so unsure as to what this does) and the BGM.
Consequently, this little video confirms Chester Barklight from Tales of Phantasia as a playable character.