After going to a few tax deed auctions simply as a spectator, I decided that although it is a good idea, it's a lengthy process and is better suited for me when I have the available liquidity to not worry about my cash being tied up for months/year. 

Today’s Interest Rate: 7.30% (👇 .02% from this time last week, 30-yr mortgage)Mortgage interest rates continue a slow stair-step lower, as the bond market senses inflation easing and anticipates (tries to) the Federal Reserve’s next move.

The entitlement process can be lengthy depending on the municipality and local requirements and in many instances if variances are required or sought, the timeline can be stretched even longer.

You might be surprised to learn that some investments we might consider passive, the IRS does not - even things like stocks and bonds. 

Notes are not considered to be "liquid assets" as securities as in a short holding period the note is not turned into its PAR amount or the same discount in a few days, not like stripping coupons from a bond or trading stocks.Dodd-Frank covers the funding at the table aspect, the loans mentioned by the OP are likely going to be covered at some point, residential, owner occupied.

There's W2 income, stocks, bonds, real estate, etc. that can all provide revenue and/or appreciation.  

The fact that the question needs to be posed in the first place (along with the fact that you are likely going to get dozens of different answers) underscores a key difference between rental house investing and, say, investing in a publicly traded REIT or a bond. 

You can get better returns, with less risk than a single-tenant NNN (everyone thought pharmacies were safe two years ago), just using termed financial instruments (bonds, cd’s, money markets).  

Also worth factoring in termite bond, which is a must. 

If all you are wanting is attention of the seller and a low ball offer, why not offer the asking price paid by the future value of discounted zero coupon bonds, say at 25 or 30 cents on the dollar?