My name is Terry Dyer and I am active @ the sales...I am also a Lic. CA Broker. I am not offering advice.... however if you are planning on bidding @ a sale you will need a cashiers check for any amount you intend to offer. NO DEPOSITS. You can puchase a title policy AFTER you buy the house. Some title companies will do a preliminary report for a fee however this is not insurance.
You will need to ensure the lien you are bidding on is not subordinate to any other liens as you will be liable to any lien that takes priority over the lien you are "buying". Generally it is the first that forcloses and the second is extinquished.
The owner/tenent can be served with a 3 day notice but beyond that if you don't get them to move out you could have an unlawful detainer action on your hands. Best to offer them some money to move out and have a contract that states the terms and does not establish an tenent / landlord relationship.
As far as buying from the bank after the sale remember that the agent representing the bank is going to ask market price for the house, the point in going to the auction is to buy at a discount to market pricing, this comes with the obvious risks.