I would strongly recommend having a real estate-focused accountant look at your situation and prepare your taxes for you, as you are now treading into complicated waters where you can get yourself into trouble if your not careful!  

Is there a new water service copper line or an old lead water line ? 

Vibration can be caused by loose pipes banging on the studs or it could be from high water pressure.

This goes back to doing more due diligence - talk to investors who have properties in those areas and to 5 experienced property management companies (instead of just 3) who will tell you what properties are renting for, potential problems, tenant base, etc

As the landlord we set the standard, I set my security deposit based on the risk level to me as the owner / manager. 

We only did two specific LLC 's based on the address of each property because an accountant advised me to, but I am wondering if this will work?

So any person that comes your way, you evaluate them based off the probability of the listing being closed on(via representation as the buyer or seller, or both).Someone offering 10% under list isn't a tire kicker; they're looking to get the deal done.

I would only be focusing on only one area and market and the based on what I am hearing, the full turnkey service might not be the best way to go... 

The house is a 3b/2ba 1,895 sq ft home but an additional sunroom built in which brings sq ft up to 2,055 (based off tax records my agent found).

Hardest part is sewer and water.