Both are business propositions that pure lenders don't entertain, and both require deals so sound (so good) that you can handle the equity partner's dilution effect and still feel like you aren't being screwed.

Here's a dead simple way to compute the max price for a pure income property.

This is pure HML (no credit check) for a 5-year fully amortizing term, so the terms are not out of line with the market.

When I search purely residential areas on LI for "multi-family" - there is never if any multifamilies available. 

From a purely pragmatic standpoint, it's possible to do turnkey properties out of your area.  

However, I think there are not that many markets where  you can just buy a house and sit back to cash the fatty checks.  

However, for the purposes of a purely theoretical discussion, pubs are interpretations, not the law, and their interpretation of 23101(a) sounds like a stretch to me.

I would add to use separate entities; purely as a play to diversify liability; get e & o for your business; you will have property liability with the building / rent loss & umbrella for tenant issues.  

Such vehicles would allow you to rollover your funds tax-free into an IRA - but with a broader range of investment choices beyond just managed funds and conventional stocks, etc.A self-directed IRA can invest in Bitcoin and real estate, as examples.The key to understand is that this is purely a diversification of your tax-sheltered retirement savings. 

Also, a lot depends on your strategy...if you are planning on using equity to grow, lack of appreciation is a lot bigger of a dealbreaker than if you are buying and holding for pure long term income.