It sounds more like a Short Sale than Bank Owned. It also sounds like maybe the agent is doing both ends of this deal? If that's the case, I would probably give a real estate attorney a call. I included a link to the California Department of Real Estate page on how to file a complaint in the web reference. You will find a lot of information on that site.
All of those items would have been written in if you had been my client. There are too many horror stories of items walking off at the last minute. My hunch is that they are probably not written in, hence the change to the MLS sheet. If you have a copy of the MLS sheet from when you first submitted your offer, I would make sure not to lose it, you may need it for your attorney or your complaint to prove the change was made.
The occupancy of the owner's (who are now tenants if the property is bank owned) should have been part of the initial purchase agreement. If it wasn't, I would talk to an attorney about it because even if the "owners" agree to be out when you sign closing documents, if they aren't ethical , why would you rely on them to keep their word about a move out date? If you need to evict them, it's better to be ready so you can start enjoying your new home as soon as possible.
Also, sellers, unless they are agents and have inputed the listing into the MLS themselves, do not have access to make those changes. They can certainly request those changes be made of their agent, but most people don't change things after the fact.
Let me know if you need a referral for a real estate attorney.