Based on your comments or fears about tenants one of the options that you should eliminate is renting then self managing. 

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If you understand screening you eliminate the problems of them not paying their part or higher maintenance.

Truly self-directed Solo 401k plan also comes with checkbook control and need for a custodian is eliminated.

A licensed surveyor can probably give you an estimate of eliminating the flooding problem, or tell you if it is possible at all.  

Further, sheltering income via a retirement account does not eliminate the tax, it defers the tax until the income is recognized as a distribution from the retirement account (mandatory distributions begin at age 701/2.).  

Now if you build from the ground up or do a value add lease up with vacancy you can get a higher cap rate.The ones that are already stable in great area the owners will  not let go at a really high cap they will just keep the cash flow then eliminate their equity gain from buying 4 years ago.

In institutional real estate deals, financing contingencies almost immediately eliminate the bidder.

Real estate as it was taught to me 40 plus years ago is a belly to belly business.. you cannot have consistent success trying to close folks on the phone unless they do not live in the market.. its too easy for them to simply blow you off.  

Other renovations included new roof, appliances, AC, flooring, lighting, paint, conversion of 100 amp glass fuse panel to 200 amp thermal CBs and the elimination of gas lines.