There is no published amount of time. So perhaps six months or more.

Not really, other than to ask your employer to provide the information. You could also try calling CIS Customer Service.

Contact the consulate or embassy that issued the visa and request to get a corrected visa.

If you have a work permit, based on H4, then yes, you are allowed to work.

Yes it is normal. There is no rule or policy to issue a prima facie letter prior to biometrics.

There is no way to do that except to try filing the visa application again. But you could try changing the passport.

It will be denied. Under the regulations you must be in marital union including joint residence until your oath ceremony is complete.

Most likely the fiance petition would be faster.

You can file once you have been in U visa status for three full years and not before.

How did your case get dismissed? It turned out that you are in the U.S. in legal status after all? More information is needed, so see a lawyer.