Ok well put it this way. All the bosses you fought up to Shang Tsung have the same fight pattern. You can either do the stay away and do long range attacks or you can run quick launch or just get close and do a quick launch, do a 2-3 hit juggle with a throw. If you do more than 3 hits, they will counter you or disappear, reappear like Reptile. Repeat this process until it is done. Same applies to ko-op. One guy can be throwing projectiles and the other be juggling or both doing long range attacks.
I will say Kintaro just flat out sucks. He was sooooo much better in MK2 arcade than MKSM. You can take Kung Lao and do 5 dive kicks, move away, repeat. He will be dead in 5 minutes. Ko-op with LK and KL owns even more cause Kung Lao can do the dive kick repeat and Liu Kang can do his fire balls. You can also do the quick launch roll back and forth with LK. If kintaro keeps getting hit over and over, he never does his teleport stomp.
So Shao Kahn has an easy pattern to beat him once you get it down. STAY AWAY from him. Do long range and stay further back. You have the option to pick up Kintaro's head but only if Kahn is further away from you, otherwise, he will be in range to charge you. Just run around in a circle hugging the outerpart of the area. Everytime he does a projectile, shoot one at him. By the time he fires it, you will be a little past the line of fire. Once you hit him, repeat until 2n part. So you get Kahn to the 2nd part of the fight with his hammer. This is way easy for ya. Keep longe range from him, like close to the circle running in a circle. He does about 6 charges before he does his spin. I would just hit him longe range when he does his overhead slam with his hammer but, save your blue meter cause once he starts swinging, you will want to use your long jump once, then run a bit, long jump again, then jump with a double jump at the peak of your jump towards him. By the time you jump, he should be close or just slammed his hammer down. Then he is stunned. Hit him with a projectile. Just one, then pause for 1.5 sec and lay a couple more on him. Reason is he gets hit with the first but, when he gets back up, the next 2 or 3 projectiles do not deal him damage.
Ok so this is it. Practice with this info. It works. Yes I fought a good beat with the 3 bosses a few times before I beat them and it appears these are very workable patterns. I wish it would of been harder frankly for these seem like a basic foundation for beating their bosses. Fun nonetheless. Enjoy.