. - I created a picture of a fictional "perfect" fund that met all of my criteria. - Because nothing really came that close, I ended up just buying notes directly.

A metal one, or wood?

Apt 2 rented at 1300/mth (2 bd)I would call the rentals B-/C because they are in a giant metal shop and low grade materials.So gross income of 76K annually.Expenses:Insurance is currently $14652 annually but that seems way too low when SFH go for that muchTaxes are currently 2800/yr, but I expect those to nearly double if I pay his asking price (so let's say 5k/year.

A metal object doesn't care if it is 20 degrees with still air or 20 degrees and windy. 

Yes correct, on all of that  Rehab I can do it all built houses all my life,Work for a sewer excavation company currently   sewer mainline needs fixed if I want to flip it $7,000Roof I would redo ($4500) has metal on it now but looks original Vinyl windows ($1500)I haven’t seen inside of it yet, but renters been there 15 years so kitchen remodel $10kAnd then possibly bathroom and flooring.

The spiral metal staircase leading up to the front door was so steep that after a month our knees were in pain. 

That's the amount the property has been appraised at with two homes, waterfront, and a large metal building with a one-bedroom apartment.

Landfills make me think: odor, smoke, noise, bugs, and water supply contamination.Construction on top of landfill: additional costs, abnormal settling, off gassing, heavy metals, and surface leaching if a capping fails.

That all said there will be sellers who could give a rip about their credit and just want out.. but if it was me I would have as iron clad of disclosure agreement signed by your seller as one can possibly get. the Buyer we dont care about the buyer they already know the risks if they lose their money tough luck on them.

Is it ok to place metal roof over shingles?