In this case I suggested a 10,000 gallon water tank with just one of those meters attached to it.

(Respectfully- Please don't tell me to save up and quit my job it's just not realistic for me and won't be anytime soon)If you read the threads on BP concerning wholesaling, you should be able to draw a few conclusions1. 99% of people trying wholesaling fail2.

So, what’s the trick?

This Wikipedia page gives different wall types and how well they block sound.  

Is there any legal action one can take or is it just a lost cause?

I was just listening to the BiggerPockets podcast and James Dainard says he spends 350-400k for an ADU.

Follow the lease and the laws in your state and start the eviction process.

Are you focusing on adding them in the general PHX area? 

As to asking the IRS reps, let me limit my comment to just three letters: LOL

We have a 14-page management contract that we've added our real experiences to over the years, with the intent of protecting both us AND the landlord.