It seems to me that the child is living with you, but is not immigrating with you since the child is a U.S. citizen.

You just need to wait and they will notify you.

You can try again to get a more favorable opinion. You may also be able to convince CIS that you are not in fact subject to 212(e).

If you lose your legal status in the U.S., your wife will also have no legal status.

The passport she used when she came to the U.S.

Yes, your employer can request consular processing instead of change of status, regardless of whether you are currently in the U.S.

At least in theory one must file an AR11 to report any changes in employment. I have never heard of anyone doing that.

You should only use the H1b if you are coming to work in the U.S.

Pending means you filed the application, CIS accepted it, and has not yet made a decision on it.

If you are asking who can be a derivative immigrant on the DV visa, it is a spouse and minor child.