You are eligible to continue working as a permanent resident with that stamp.

Check your petition to see if that was the date requested -- if yes, then no USCIS error.

Your petition number and also your husband H-1B petition information -- bring both to the interview.

No reason it can't qualify. The consulate generally looks for an investment in excess of $100,000 though and a physical location in the U.S.

I would not worry about it and go ahead with the I-140 approval in the I-485 submittal.

Yes you may have multiple I-140's pending. Perhaps you qualify for EB-1B so you have a different shot at approval.

As long as you had a good faith intention to go back to Employer A after green card approved when the I-485 was filed there is no fraud. If no...

Start by asking for a complete copy of your file and then get new counsel. This is unacceptable behavior. You are entitled to know what is going...

Yes this is doable -- you have 60 days to join the new employer if in the U.S.

You need to retain a U.S. criminal attorney to resolve the warrant. Perhaps they can resolve without your participation.