The NPI Number for who does the work goes in Box 24J on the CMS 1500 Form - if it is required. The NPI Number for who gets paid goes in Box 33a - always.
Your Q2: The NPI Number in Box 24J needs to be the number of who did the work. If the phlebotomist does the work, and if s/he has an NPI Number, the phlebotomist's NPI Number goes here. For the California commercial carriers, it makes no difference if the number is there or not. I cannot speak for the carriers in your state. (We can put the number there, even though it is not required, and the claim still gets paid properly.)
Your Q1: Call and ask. Or submit without the NPI Number in Box 24J and see if the claim gets paid. Or Google for medical billers in your state and call and ask them.