Buy and Hold investing is a great avenue to begin with as most people live their lives off of residual income. 

Consequently,  there's rarely enough of a deviation in price between these auctions and what you can buy on the MLS/elsewhere with full diligence capabilities to make these transactions worthwhile. 

Once you can define what you are looking for then you can create your "Buy Box". 

I want to buy it and build a prefab home 3/2 around 2k sq ft.   

I have helped a lot of first time investors learn the process and successfully buy their first investment property. 

You can also offer to lease with an option to buy to tie up the property until you are ready to purchase. 

I buy to rehab and turn into rentals so Pinson, Pelham, Bessemer are a great fit for the areas and returns I'm looking for.

that OR consider buying a property you could short-term rent to people who literally just want to visit the casino if it's a large/decent one. 

Buying a new primary residence has nothing to do with the capital gains exclusion.It is when you go to sell the new house down the line you'll run into a problem.

Again, I do not want buying the multi-family home to block me from accessing lending for the second home when I move.- Does anyone see any flaws or can offer some improvements/considerations to the financing strategy of this plan?