If so what is to most accurate way to find cash buyers? 

You're second paragraph is actually very accurate for MLM/affiliate marketing/network marketing/Amway, real estate agents are not in that league.

Also, how do I go about determining an accurate percentage for expense costs?  

The meters that accurately detect the parts per million of CO cost thousands and thousands of dollars.  

Can you price out your renovation budget by the room or the job so you can get some more accurate input?

Also, being a firefighter, I could accurately assess how specifically the fire damaged the structural elements.  

You can ask for any discount you want, but there's probably plenty of money out there, assuming your numbers are accurate, that would buy it at a 6% yield.

This is going to be a fast paced, informative 90 minute seminar on how to quickly and accurately analysis a property.   

Your marketing needs to find off-market deals, your analysis need to accurately determine ARV, your negotiating skills need to enable a contract at a well-below-market price, you need to be able to evaluate the property for for rehab costs accurately, and the easiest part is finding buyers. 

Rentrange.com tends to be more accurate but costs money.