I never got to Jade, there was too much misleading information out there, so I stopped trying.
Set the matches to 2 rounds in the main menu, and don’t lose a single round up until the Shang Tsung fight.
On the Shang Tsung fight, get a double flawless victory against him, and then perform a Fatality on him.
If Shang Tsung touches you and you don't get a Double Flawless victory, beat him anyways and when it says "Finish Him" you can pause the screen and select a new fighter (It won't count as a loss).
Once you get a Double Flawless on Shang Tsung and do a fatality on him, Classic Jade will come out to fight you on the Goro stage.
If you set the counter to 30 seconds, it's easier to do.
Hope that helps.