I have been listening to the podcast for a few months now and watching the "Real Estate for Rookies" YouTube show and I've been learning and also reading different books on real-estate investing.

However, it sounds like you are confused about the different types of auctions that exist on Auction.com. 

Each deal is different of course.

The 10k is the difference in the points.With lender 1 will cost 10k more in points.Lender #2 is kind of unknown.

Another option is a DSCR loan where some lenders have shorter seasoning or waiting periods- I've seen some that are three months which can make a big difference for an investor getting cash out of a deal and using it on a new project.More info on DSCR loans: DSCR loans won't use your income to underwrite the loan.

Check out the different Forum Categories here as they can answer a lot of questions you have just reading through.

This Wikipedia page gives different wall types and how well they block sound.  

Purchase price: $630,000 Cash invested: $120,000 Completely gutted this property, brand new electrical, furnace, propane, finished basement to create separate unit.New garage with rental unit.

Then look at different REI to scale to that number.  

Most do a LLC but again it can be very different - for example I have a C corporation, had a S corp, had a LLC etc. and each one for very unique and different situations.