Yes you must submit an AR11 to submit your change of address.

The appropriate filing category is C9.

Yes you may work if you were admitted in the status you requested the EAD.

Contact NVC to allow you to update the DS260.

Yes you may later visit the US if you surrender your GC.

Medical may be submitted at time of interview.

It will take 30-90 days for NVC to review your documents.

I agree with my colleague - try to have the passport processing expedited.

Notify the officer of the issue at time of interview.

Yes you may request expedited interview scheduling.