1. I believe the fact that the law states that the trustee sale is perfected as of 8am of the day of the auction is to protect the buyer from weird liens and judgements from sneaking into your chain of title between the the morning of the trustee sale and the time you physically receive your trustee's deed.

2. The bk is a seperate issue and I believe which comes first (the exact minute of your trustee sale vs the exact minute of bk filing) technically wins that battle.

Many trustee services time stamp the trustee sale for exactly this reason.

If I bought a killer deal and a trustee tried unwinding even though the sale took place prior to the bk, I would sue, and win. If I bought a thin deal, I would move on.