1. I don't know who are you.
4. I don't know what going on is?
The WH-word doesn't replace a subject, so it's moved to/inserted into the subject position.
The verb is BE + -ing: it stays together; i.e., is going on.5. I don't know what's happen?
Try, I don't know what has happened. The verb is Present Perfect. Contracted what's represents two forms: what is and what has. Look for a past participle--you'll know whether -'s represents has oris.6. I don't know what happen is?
The verb is HAVE/HAS + Past Participle: has happened. It must stay together.