A few of the houses I am interested in were not bid on at the sale and the owners are deceased.

If you do bid, 10% down payment is required to bid on the property.

Depending on the state, this means they must give you proper notices and publish proper notices of foreclosure and set a sale date to sell the property at auction to the highest and best bid at a date in the future that is no less then the law allows in that state. 

http://www.mercurynews.com/2017/11/25/bidding-for-...I read this article and thought this was an interesting concept. 

It's a reverse auction where you post the job, info, and photos of what you want done and the max you are willing to pay and contractors bid the price down from there.

I am in need of getting three bids on doing a rehab that I'm going to buy.Let me know if you are one.

Once you win the bid, there no way to back out of it is there? 

A) Contractor A bid $1,000 to fix 2 leaks, replacing 10 feet of plank wood 2 pieces, replace shingles, place plastic cement and fiber glass along the valley. 1 year warranty, $300 advance, $700 when complete.

It sounds like most people think they know what they can get out of  a property and are willing to bid fairly close to that end number. 

There's some benefit there in that I can always change my mind about selling if I'm not able to get the asking price I want, so I can retune the analysis with new data if I find bids coming in too low.