After that, I know the routine for getting local banks to give me commercial loans on sfh.

You also mentioned this is going to take up most of your savings which again makes me uncomfortable.  

Some of the kids who were walking by to go to school who noticed this “routine” even called me “Four Flats” because every morning the four tires of my car were flat!

All capital improvements, not routine necessary repairs, get added to your purchase to determine your basis.  

It seems conventional Freddie/Fannie loans are capped based on income severely limiting my financing and in Los Angeles I'm finding I would need to put over 50% down (which I can, just uncomfortable being so un-diversified).

They also will move the location of buttons that you interact with, which disrupts workflow routines that you have and makes the day-to-day harder. 

You've listed all of the most common strategies.What I see most wholesalers get wrong is they don't have good follow up routines.

If other tenants find out he was violent and still living there, they may feel uncomfortable and you could lose good renters.

If you're going the umbrella insurance route, make sure it will cover you for several things including just the routine slip and fall (like mold or earthquake).

Having to cancel on my contractor twice because it went under contract 48hrs beforehand, especially as a new investor, made me uncomfortable and a bit embarrassed, as I don't want the contractor to think I'm not serious or I'm a time waster or I'm backing out.I'm not sure what type of contingency would be appropriate for a cash purchase in this case.