The EJB Menu does not access Noob Saibot or Rain as playable fighters in the ARCADE version of UMK3. In the arcade version of Ultimate MK3, even though it saddens me to say this Rain is nowhere 100% playable. In the Wavenet edition of Ultimate MK3 you could play as Noob Saibot by starting a 2 Player game and selecting Kano as your fighter. Then before the match begins you'd hold Back, High Punch, Low Punch, Block and Low Kick and Kano would turn into Noob Saibot much like Robot Smoke would turn into Human Smoke. In the Wavenet edition Noob had Kano's combos and his Down, Up Teleport Slam. This was only achievable in the Wavenet editions which were only in Chicago and I believe California at the time. They quickly died out and were scrapped and what boards or ROMs could be out there are still up for debate.
Rain and Noob first became playable in Mortal Kombat Trilogy for the PC, PlayStation, Saturn and Nintendo-64 versions of that game. Nearly all fighters were playable depending on the ports of Trilogy you were playing. Not too long after the release of Trilogy, Ultimate MK3 made its way to Genesis and Super Nintendo and that is where Rain and Noob Saibot became playable on any version titled Ultimate MK3. The 16-bit versions are nowhere near as good as any other version of course. Sheeva is absent in them as well.
For the MAME and other arcade emulators there are a few cool cheats that will allow you to play as Noob Saibot or Rain. You choose any fighter, and then enable the code the Noob will replace them. Noob has no special moves nor finishing moves. You always fight in Noob's Dorfen and Noob has all of Kano's combos. In the MK3 version it is a shadow of Kano and un Ultimate MK3 it is a ninja shadow. To enable Rain you choose any ninja, and enable the cheat to make their color purple, that is all the cheat does so no matter which ninja you choose, you enable the cheat to turn them purple and still have the moves of the ninja you choose. There is another version of MAME that has a Trilogy style Ultimate MK3 where you can choose various options and Rain and Noob are fully playable with their moves. They also have a Pit move and Babality and Mercy. This version is available on Kailera (spelling?) and was made by programmers. In that version you could have Ultimate MK3 or Trilogy masked Sub-Zero moves too. Lastly, off topic, there is another MAME ROM hack that enables Noob and Rain as well but I haven't played it to see what is different about it. Similar to the MKII hack the cheat code enables them and they have their moves from Trilogy hacked into the game.
As far as Rain goes, in the arcade UMK3 he was just on the demo screen and there are 3 different views; the first is he starts out using Reptile's fighting stance, runs and performs HP, HP, HK, B + HK on Shao Kahn. The next shot you see him simply falling over and in another shot Shao Kahn falls over and Rain does Reptile's win stance. In all of these 3 different attract mode screens if you look at his name it isn't the same font as the others in the life meter. Also he is always fighting Shao Kahn on the Blue Portal stage which are other indicators it isn't true. When you fight Motaro or Shao Kahn as Human Smoke it is on their respective stages even though the entire ladder before them it is the Blue Portal. The 717313 = Rain Can Be Found In the Graveyard cheat tells your to look in the Graveyard. Occasionally the Cage headstone will read Rain. It is random much like the dates and names of the programmers you see. It took me a while to figure out that cheat but at random times CAGE headstone will say RAIN giving us another clue that he isn't in the game.
Rain is my favorite character because of the mystery that surrounded him in UMK3. We see a ninja during the attract mode and we believe he's in the game somewhere but come to find out he never really was. However everyone else was. It was a nice trick and a nice nod from Ed to Prince and his Purple Rain song and possibly film which showcased my favorite colored Cuda.
