You can do it yourself. There is no requirement for you to have a lawyer.

A drivers license, and bank statement addressed to the person could help.

There is no requirement for one to quit their job abroad, in order to get an F2 visa or a B2 visa.

Try your best to be as accurate as possible.

Yes, you should be eligible for certain public benefits. No, if you are approved you do not have a prima facia approvable case. Rather, you have...

Sometimes people travel with something other than a passport, such as certain derivative asylees and stateless people.

No. Just bring evidence of his current salary to the interview.

There is no problem, they can do it. Just notify NVC that they are seeking adjustment of status.

Continue to follow up, and consider seeking congressional assistance.

It means you have to wait to get the approval until there are numbers available.