Lawyers have told me that my priority date will be current within 6 months

Attorney Fleischer gave a great answer.

Both of us are living in China, since 1993. We married in 1988 in Philadelphia, both are US citizen.

This is not an immigration question. Contact a family lawyer by visiting the closest US Consul to your location in China.

How to bring my parents legally into the US?

I agree with Attorney Fleischer ... you need to be 21. Plus, if you were born in the US, I'm going to guess that your parents lived in the US w/o...

I passed The Citizenship test And I got A decision can't yet be made about your application, and everything under B checked.Y N?

I agree with the other attorneys. You shouldn't have filed for naturalization if you and your husband don't live together ... for whatever reason.

You answered your own question. The person being sponsored can not get a greencard at this time. Talk to a lawyer to understand your options.

Do I have a chance to get B1 visa after I overstayed K1 for almost a year?

Although in theory it is possible. In reality you will probably be refused. It won't hurt to try.

L2 visa expired with valid EAD

The other lawyers are correct. Unless you want to travel internationally, the I-94 controls.

Can my new employer extend H1 based on approved I-140 with my current employer?

Attorney Ferrari is correct, company A may not be too happy if you go to company B. Get a lawyer.

I-485 form - Part 3. Processing Information

That is good detail. Like my colleague stated, if they have questions, they'll ask.

Can I work on L2 visa without accepting payment?

NO ... do not ruin your future in the US merely because you are impatient. Wait for the permit to arrive.