Kodak was a industry "beast", a definitive "safe" investment, until it wasn't, and it went to trash in a flash.   

Maybe an occasional HVAC.

I've been eyeing land in Central and West Texas, and they occasionally have some interesting opportunities, but some of them seem too good to be true. 

My bookkeeping firm provides me with a steady active income, which allows me to keep doing deals, cover unexpected expenses, and navigate the occasional black swan event.

Again not a big deal for a home owner with one single mortgage to keep track of if their loan changes services occasionally, but with a number of loans all changing companies multiple times in the same year, it becomes frustrating trying to keep track of all of these changes, only to have more changes.   

Yes pretty common, minimum downpayment is generally 25% (occasionally that 20% will work) but just depends on your situation.  

When you mentioned you did your homework on the turnkey property, if that were the case you would have had a really good idea what the property was worth before you offered on it (of course sparing the occasional rogue appraiser, which may be what happened to you... idk) and certainly before the appraisal.

Although, with all of the trips going down to Texas, having been burglarized, and in an area next to an active trap house that was selling drugs on the corner... occasional gunshots in the distance..

My bookkeeping firm provides me with a steady active income, which allows me to keep doing deals, cover unexpected expenses, and navigate the occasional black swan event.

Build a reliable team on the ground, plan occasional visits, and trust your general contractor to handle the day-to-day.