Do you expect to live long past that time frame and be healthy enough to fully enjoy that great cash flow and deal with the landlord stresses?

I’m new to this and know very little but I enjoy reading and researching.

These tenants are on a joint several lease, and it's not obvious whether joint tenants can violate each other's legal right to quiet enjoyment given the unified nature of their rights and responsibilities. 

If you can house hack, like @Nicholas L. said, that is ideal because you will need the least amount down to do it and can get the enjoyment and landlord experience out of it.

Should I get the police report and send a letter to the upstairs tenant reconfirming with them the stipulation in our lease of quiet enjoyment? 

If you are this close to the border or cost you need to purchase through a corporation or through a bank trust (Fideicomiso - Think of this trust to be similar to an inheritance trust or a living family trust in the US.)At all times you are the legal owner of the property, the best way to see it is as a permit or license that allows you to purchase, use, enjoy, rent, renovate, inherit, etc. a property in this zone.

I really enjoy the property manager, they're getting 4.9 reviews for it and their team is great to work with.But I’ve only had a handful of profitable months, most of the time I’ve been paying either the mortgage myself or unexpected cleaning & maintenance bills, and my savings has run to zero, so it’s a big loss so far.

I would imagine wherever she went the new landlord is enjoying her company.

I also enjoy the poster's contradictory claims, waffling and changing the rules depending on which side of the fence they are on.

They discovered that we feel a loss twice as hard as we enjoy a gain.