Model the portfolio over time with projections for appreciation, rent increases etc., don't assume that paying off mortgages is the best way to generate cash flow.

(I watched this a long time ago so if I missed anything please feel free to correct me).The Section 8 BRRRR Strategy That Beats Regular Rentals - YouTubeHis theory: Is basically a lot of section 8 tenets are used to having crappy landlords living in crappy places.

Basically will they value it as a multifamily property (5+ units) using NOI and cap rate or will the quad be valued from a residential (comp-based perspective).

You basically can't purchase a SFH in Taney or Stone country because of the regulations against STR - be wary of people selling their homes as STRs (they are probably trying to get out before more regulations kick in) - you will not legally be able to rent it.

Building wealth through real estate is not a get rich quick scheme, and you should look to project 3-5 years out to really see some great gains. 

what are the numbers on the townhouse - projected rent and all expenses? 

You can do a 1031 exchange and use those funds towards another investment purchase (basically a tax deferment).

I know contractors who will quote $100 a sq ft on a rehab, but can get the project done themselves for significantly less than that.

I have a new build project that I am in the middle of building with the intent to sell once finished.

Normal Conventional loans do not support these types of projects because of the conditions of the homes.