It depends on the embassy backlogs and visa priority.

You should receive decision about 1-2 months after biometrics.

The case should not be denied but you should contact USCIS right away to request rescheduling.

Yes you may submit this to establish your domicile in the US.

Yes you may provide this as proof of domicile.

Yes you must disclose your marital history honestly and fully.

Refer to the I864P to confirm if the cosignor qualifies.

Yes convert your salary to US dollars for affidavit of support purposes.

This is common as the cases were separate and distinct and not jointly filed.

Expedited requests are very difficult to have approved so likely will need to wait.