Yes you may do so while the i485 is pending.

Best to be honest and transparent and if answer unknown, submit a FOIA request for your full immigration history.

Contact USCIS directly to report the erroneous receipt notice.

You may indicate your overstay status when indicated.

Best to be outside of the US for more than half of the year before returning again.

Yes your spouse should accompany you to the interview with supporting evidence of the marriage.

Use form AR11 to change the address and the G28 should not harm your case.

Those should not be an issue as payment will have been made.

No there is no issue and you may file the forms separately if not otherwise eligible for adjustment.

The applicant can apply on their own using form DS160 and without invitation letter.