This isn't relevant to all markets, but for mine the tax assessment is actually pretty accurate with the sales price generally being within 20%.

Now it is worth 10x what he bought it for (based on my cost estimation software I use in my industry and knowing the cost per sq ft very well in my area, I am inclined to believe he is very accurate), he states he just wants X dollar amount for it and even after the gifting of the down payment, there is easily enough equity remaining to make that happen.I don't ever want to acquire or amass wealth through shady deals or taking advantage of anyone, so I know the statement of two players playing each other is a false one.

Would anyone be willing to pay for an accurate rehab estimate?

My point, though, is that while it's not entirely accurate, it's not as entirely useless as some would have us think. 

This might be a rookie question but I never had anyone clarify it for me, Is Zillow accurate ?

I'm sure it's helpful if there's some motivation for the Agent to help me out so I'm wondering for those who work with Agents helping you to get accurate information, do you pay them or give them something, etc?

I have called several different property managers in the different areas to feel out rents but when I am searching the entire metroplex and the areas surrounding it, rents vary and really the only way for me that I am aware of to accurately get a feel for the rents in that neighborhood is through a quick CMA.  

From my understanding, which may not be accurate, I feel like it is more of an abstract, subjective, flexible, and fluid rating based on all of those items that you've mentioned. 

The website gives a calculation on property taxes but I'm wondering if it's accurate for me as an investor?

Research has shown that if you take the average of a large pool of guesses as to how many jelly beans are in a jar, it will be pretty accurate.