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

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

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.

Then look at different REI to scale to that number.  

Being a super host and knowing how to place claims are two different things.

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.

There are times when the market increases or decreases rapidly.

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. 

I’ve read a couple books but I am always willing to learn… Also if you were 21 , what would you have done differently?

Total profit less closing costs and commissions will be about 42,500 each or 85k total.I would for sure get a construction loan, may be worth approaching 2 or 3 different banks and getting separate construction loans from different banks.