I'd want to know why their credit score is below 600.

Find an inspector who works with investors (ask your local REIA for referrals) and then get the no-frills version of the final report.

How do you value truth vs. your own preferred version of reality?

One of them is US citizen with no credit score. 

It obviously will depend on your entire application (credit score, D:I ratio, etc) but let's just say you're pretty green across the board.Also, do you recommend trying to find a local credit union (hard to find one that will do a HELOC on an investment prop based on my several attempts) or going to a public bank?

Also try to increase your credit card limit will short term increase your credit score (as long as you don't go deeper into debt) I suggest looking up Credit Karma to help you with ways to boost your credit its a free app.

I just make sure that I can justify my low offer by giving them my version of the financials.

The short version is my wife & I have multiple properties... 4 of them in the USA.

Quick version: Can I cash out refi to a commercial loan and then refi back to a conventional mortgage?

I received notice that I’d be moving back to an International project shortly (score) and with no tools left at the house, I actively began seeking out contractors to just get the house finished and done.