Yes the case would be forwarded to NVC to be transferred to Embassy for interview.

Yes you may expedite but only after the visa becomes available.

It may if he misrepresented himself to obtain the benefit.

You would indicate you were arrested in the appropriate section.

He must wait 4 years and 9 months from date of residence to apply for citizenship.

Best to consult with an attorney about prospects for change of status with overstay.

The RFE may be related to the underlying I485 application filed with I360.

Yes anyone who is a USC or LPR and have sufficient household income may act as cosponsor.

Yes the pandemic and home country conditions is valid basis to request an extension.

Each applicant will require a separate DS260.