Once you find the strategy, pinpoint a Crystal Clear Criteria for the properties you are looking to purchase and it will narrow down what you look at. 

If a CPA has 40 years of experience, I would lean towards his answer unless you can pinpoint something in the internal revenue code, treasury regulations or a court case to show that he is wrong.All professionals can be wrong but he has a certification and experience on his side.Unless you are a 5% owner in the general contractor business, your hours working the W-2 can not be added to the real estate professional hour requirement.

"Homework"; -Define financial objectives/goals that are numbers based - Gather realistic personal financial information and what you think you can afford and cross reference with goals as well as an expanded search of various markets both outside of Austin and out of state to research availability - pinpoint locations in state/out of state (Education phase)- meet with lenders, either commercial or otherwise to see what you indeed qualify for once you've narrowed down property types and locations (Education phase)  - Start interviewing PM's if you're looking outside of your current investing area and will not serve as your own PM (Education phase)- Get with an agent in your desired area and for your desired property type and start looking at deals (Shopping phase) - submit offers/LOI  armed with your information from Education phase & Shopping phase (Transaction phase)This is the breakdown that can be helpful as an outlined plan of action/phases for some of the out of state investors clients I have, but should work for you to start with in TX as well.

For example, you could pinpoint a location of interest and check the square footage of storage versus number of people in a one, three, or a five mile radius.

Also you can see active water usage live online now which can help pinpoint issues like squatter moving ,  leaks etc2.

For starters, it's probably best to pinpoint a few neighborhoods you want to invest in and go from there.

Other than that I couldnt really pin point any places it was getting in - maybe vents in bathroom but generally seemed pretty pervasiive so yes it does kind of feel like i might be looking at mission impossible for sealiing everythiing off.This is indeed first communication from tenant.  

Ideally if you can find 3-5 similar properties you'll be able to pin point the ARV.

I believe property inspections are a waste of money, they don’t get specific and all they do is RE come from you to experts who will be able to pinpoint what the issues are.

Estimating the percentage is something I can imagine, but there are variables that I cannot pinpoint.