To fight Jade, you must only use the low kick, block and directional buttons in the match before the match which is labeled with a question mark.
To fight Noob Saibot, purposely win 25 matches in a row in VS. mode.
If you're 1st player, highlight Liu Kang and press Up+Start. If you're 2nd player, highlight Reptile and press Up+Start. As a result, they will pick your character for you.
At the options menu, highlight "Done" and press Left, Down, Left, Right, Down, Right, Left, Left, Right, Right for Test Mode to appear.