Ok, that could be as minimal as literally hours per year, like <10 per property.

To minimize upfront costs, explore down payment assistance programs, creative financing strategies like seller financing, or rent-to-own agreements. 

Waste of time.

Obviously tough to give advice based on minimal info and no info on your personal situation.

It’s on the rise but you just have to be selective regarding location and try to go for turnkey or keep it minimal regarding rehab  So you don’t have a nightmare story trying to manage a rehab from Out of Town. 

"there are plenty of reasons why a landlord should care who is looking at their property, theft and their own personal safety being the first 2 that spring to mind, followed closely by not wanting to waste their time" These are valid reasons but depend greatly on your market and who is showing the property. 

You will be required to get a foundation inspection report on top of an appraisal and you are required to pay for both.That is why I said make sure you do your research because if you pay for an appraisal or foundation inspection report and its not within guide lines you will have just wasted anywhere from $650 to $1000.00 non refundable.  

Do not waste your money on his course.  

, I really need to keep it simple and minimize risk since I live abroad.

Also a non-starter is your hyperbolae; "toxic waste lot's"......