So I have been getting things to gather and raising money for my second flip.

How do I get the correct or close to accurate future assumptions?

@Emre Görü The above comments regarding the Coachella Valley market are pretty accurate. 

airdna.co is one, I've ran analysis on my own area though and the numbers weren't very accurate, lets just say I would be retired If I was actually earning what they say people do in my area.

My target property range is 5-50 units.Long and short, when I generate my list in ListSource, it does not appear to provide accurate data for this county.

We've also gone down to zoning and planing and gathered some good information.

Accurate data is not a priority.

If not, why is their argument not accurate?

To be blunt I have no clue as to taxes, vacancy, insurance and cap expenses on this type of home so my WAG would be $250/month (I have no idea how accurate this is but I know this is significantly less than I would use for a detached studio standard home) for a cash flow of $250/month.Ideally the forced appreciation is real significant. 

Lastly, like any other close, make sure your financial documents are in order... you'll need copies of taxes, bank account history, investments, etc. gathering all of that information can ne a pain if you aren't organized.