1. He will ask you what you like.

2. I doubt what he will do.
3. Tell me what you want.
4. I don't remember what he said.
5. I know what his job is.
6. He told me what I liked.

(Are the sentences all correct? 'What' in each sentence is an interrogative pronoun, right?

Yes, "what" is an interrogative pronoun, introducing the indirect question in each sentence.