Total different world and crazy.Use some basic stuff.  2000sqft ranch style house.  

I think there are different approaches to this as one method may not be suitable or appealing to everyone.

I know no place that will rent quickly without granite or similar style upgrade.

I have read most of Grant's book, love his aggressive style, but I have not gone through any of his courses, the price point was a turn off for me.

The less invasive option would be propane fired Rinnai style direct vent heaters in each unit.

I too am struggling to find something suitable - would like to ensure I have considered all pitfalls!

Fixing this requires dealing with Form 3115 - a highly specialized project that is not suitable for DIY. 

It also avoids the hassle of going through different financing options to find the one suitable for you.

Length of tenancy depends on the property, the type of tenant, and your management style.

If it were me in the situation I would look either at the most doors I could get for the buck in a stable market, like a $750,000 16-unit multi-family in my market that is currently c-class (window unit air conditioners, dated stylings, and 10+ year old appliances, etc), extremely well located, and, based on all that, probably a good target for adding value over time and increasing the appraisal value substantially.