The savvy business person may realize these additional, and possibly unnecessary costs, are eating away at business profits that could be used to reinvest in the business and buy more properties!

I would say I turned out pretty lucky given that the moratoriums might have prevented me from evicting him until next year.

I seem to be prevented from posting contact details here but you can find him I'm sure...

Make sure to sign an affidavit that you're selling a qualified primary residence when selling, otherwise the title company will report it to the IRS and may trigger an unnecessary inquiry.

It's expensive to implement this strategy and, in my opinion, unnecessary for beginners.  

Any suggestions on how to prevent this in the future?

His timeline doesn't make sense to me, so you might get lucky and find a 25 year old power of attorney that may or may not be enforceable in your situation, but you also might find one that is much more recent and put in place to prevent the transaction you are trying to engage in.

Does this include some preventative measure to avoid those late-night maintenance requests?

I feel like I could have done better in the due diligence stage, so what have you done to prevent these types of situations?

My concern with the more expensive property is that it would eat up most of my savings, preventing me from purchasing another property unless I find an alternative financing source.