Are there any unlockable characters and how to unlock them?
I'm playing the PC version of Street Fighter X Tekken, and I'm curious to know if the unlockables differ from the console version.
No, there are no unlockable characters. All characters that are available in the game by default are playable from the outset.
There is a paid DLC pack available that adds 12 additional characters, but you cannot play those characters at all without buying said DLC.