There's nothing wrong with it on the surface, but other than the free pricing for small landlords there's nothing to compel you to use it.

Lets face it, some 10 or even 20 numbers you could just write it down on a piece of paper or an old fashioned addressbook...You mentioned:  "I'm assuming PM collect the payments, manages the lease, track tenant activities etc." 

I know it sounds simple on the surface but detailing out how this money is handled when things don't go to plan could become more involved.

Curious as to why you installed carpeting instead of longer lasting hard surface?

But that assumes you have minimal equity within a LLC and you’ve operated the entity in a fashion that cannot be pierced.

Now, to answer your questions here, you cannot own property in the US in this fashion until you are 18 years old.  

Good old fashioned calling someone up, sparking a conversation and finding out their motivation/pain points is definitely more effective than mailers.

Then you'll have surface parking, landscape, etc.

If it's just surface mold that can sprayed, washed, and cleaned up that's way to high. 

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.