At 4 it's getting complicated, and thinking of 10+ makes me angry in advance.How do you manage having internet service at multiple locations?  

Don't make it so complicated.

End of day, this is what it boils down to at core, remove all the over-complication of it, it's just Product marketing. 

I am reading about Wyoming LLC's being best for anonymity, but I want the most protection with the least complication! 

I am the only member on the LLC, I am married but I would buy this next property only under my name if it avoids complicating anything. 

I am curious though, if these deals are as sweet as they sound...I’m also curious to hear about the complications of owning/investing overseas?

While there are more complicated ways to measure this, the most practical way if you care about answering the question "how much do I make every month" is just income - expenses = cashflow.

Separately — and this is a more minor gripe — it was complicating my tax situation to pay state and local income taxes in a place I didn't live anymore.I pitched to my parents that I would sell the place and roll it over into a comparable property closer to where I live.

I am finding it complicates the relationship because I want to be friendly and neighborly yet also need to set boundaries as I know landlords need to be firm sometimes. 

That is kind of complicated, depending on the scope of the project.