You may seek asylum. Consult directly with an immigration attorney to review the specifics of your case and assist you with preparing a strong...

Credit score?

A credit report will be required to review your financial history.

You will need to consult with a lawyer to over the specifics of your case.

Moving back to Old employer on H1B

As long as the petition is not withdrawn, you can proceed with the green card application.

As a US citizen, you do have an option to bring him and the children to the United States.

Can I re-initiate I140 & file I1485 through my old employer? (Withdrawn I140 in EB2)?

I agree with my colleague. There does not seem to be an option to reinstate a withdrawn petition.

Can I have 2 I-485 filed?

You may file both and proceed on the one that is quicker and that makes sense.

He may be eligible for a bond so that he is released. Speak with an attorney to go over the case.

How I can get my Alien Number?

You can get a copy of your file through a FOIA request.

Can my new employer need to start the legal immigration process from the beginning, or can they reuse prior approved I140?

A new employer will need to file a new I-485, but they may be able to re-capture your previous priority date.