Neglecting to include, or reducing the impact of, other economic vacancy factors such as loss to lease, bad debt, concessions and non-revenue units. 

Like @Joe Edmonds said, I could live on 10 or so paid for rentals and it only takes a few to make a big change in a middle class lifestyle if you also have a W2 job and that's enough impact for me.   

If it is a long term investment, I don't think real estate cycle will make an impact to your investment. 2.

I feel having a privacy fence attracts a higher end tenant and keeps the neighbors for being such a huge impact on your rents. 

Am I thinking correctly that I can help limit the impact of property tax hikes by focusing on locking in a lower mortgage cost vs. taxes to better take advantage of inflation over time?

A large employer can announce layoffs that impact demand which pushes prices lower.

Well, turns out that if I don't report expenses, the tax cost is quite high, so it might not be an option.Anyways, still curious to know how one approach or the other would impact mortgage qualification.

I'm always wary of average profit margins for flipping as they're based on  incomplete data, missing actual expenses that have a significant impact on profit margins.  

New cultured vanity marble counter tops in both full baths.

This means that the rental income on the 2-3 additional units you don't live in have to cover your PITI expenses, and of course you're ceiling is the FHA loan limit, but that sounds like a way to get into a second property with minimal impact on your monthly cash flow when it's all said & done.