Say you buy for $800k and earn a rent that covers operating and costs.

You could take a personal loan to cover it, or a line of credit on your primary home, if you have equity

You lose now if you sell and if you rent you will need to supplement your tenant rent every month to cover your expenses.

You'll have most of your mortgage covered with rental income and, with an FHA loan, you can cut the amount of cash you need in half, possibly even more.

That should be covered in your state landlord tennat regulations.

Looking at insurance for these properties, what is generally considered to be adequate coverage, ie what should be covered and how much would be a reasonable amt.

If you find a great deal on a 4plex where you live in one unit and the other units provide you with total coverage and extra cash flow per month; then you CoC return is essentially infinite (assuming you got your closing costs covered by the seller).

Keep in mind that along with rent you also need to cover furnishings, utilities, cleaning staff, maintenance and supplies.

Is it to promote click bait? 

I took the first job I could and it wouldn't even cover my bills.Here I am three years later with my credit back up in the 600s, I have three jobs, and I'm working to get into REI.