Yes, once he becomes a US citizen he may petition for his parents.

Yes, you may request this but there could be delays in your case processing as a result.

No, not if you will be applying for her while she is outside of the United States.

It can take many months depending on the embassy where the interview will be scheduled.

It depends on whether the applicant is in or out of the United States. Consult with an attorney for guidance based on your questions.

Try your best to provide an accurate recollection of your work history.

No, you would have to wait until filing DS 160.

No, this is only completed after that I130 is approved, and the case is transferred to the NVC.

You will need the original receipt notice to travel. If the case was accepted by USCIS late, Travel should be OK. You can contact USCIS to confirm.

Yes best to renew your GC for this purpose.