Submit a offer with limited amount of contingencies and a pre-approval letter ASAP. Depending on the market a bank will save money by dealing directly with you. However, banks are slow and the house may go to auction before anyone reviews your offer. Good Luck!
Auctioneers in our area will require you to have 10% of the purchase price in certified funds at the time of the sale along with a pre-approval letter with very minimum conditions that need to be met for you to get the money. If your approval letter is predicated on a number of things, they may disregard it completely, as then it is really not worth the paper it is written on.