@Ryan Fox some great info here, but while you are correct that a service member assuming a VA loan restores eligibility to the initial veteran, making the deal more attractive, it is not strictly true that a veteran can only have one VA loan.

Bought, that is correct. 

Nevertheless, my question is the following: How do I run a proforma correctly so that from a distance I can run numbers and know I have an educated source calculated to make a deal happen and not fall through.

Like any tool, you have to know how to use it correctly or you could get, "injured".We use it to quickly sift through multiple options - and that's about it.BP has a Rental Calculator that includeds everything you are asking about: mortgage P&I, property taqxes, home insurance and percentage for maintenance & vacancy.It also includes Cap-Ex percentage, but in our experience it's a waste of time to worry about this.

But I don't believe this is fully correct. 

Once you build it correctly, you can offer it to other investors as a service.

There will be no difference in the rent - unless the TurnKey provider threw in a desparate/bad tenant to get the higher rental amount.With a TurnKey provider, you'll pay more for a property that they have rehabbed, versus hiring your own crews to rehab something.Yes correct.

Hey Zahra,Have a lot of clients working down there and you are correct, it has become a great place for investors.Biggest differentiator that I have seen has been on appraisals after the repair.

If the question had the word "animal(s)" in it, you answered it correctly.

Quote from @Sean O'Keefe: Correct, California is uniqueThis is a rather diplomatic statement, Sean  ;)