Yes, it’s perfect. “I do” is a shortened form of “I do make” — so the verb “make” is (implicitly) in both halves of the comparative sentence, as is it should be.

It’s perfect. Note in speech it will be common to hear: He makes more money than me. He makes more than me. He earns more than me.

Hi. It is fine. When comparing things in English, we usually use the proper auxiliary verb the second time to avoid repetition.