Credit score- the higher the best. 760-780+ generally gets best pricing for investment property loans with most lenders.

@Jason Staine I used my local credit union where I also have personal and business accounts. 

When it comes to qualifying for a loan like verifying your income, credit score, debt to in come ratio etc, will it help to say that I receive additional income from my househack tenants aside from my w2?

I have the similar settings as @Bruce Woodruff "guest must have a good track record" and I send a pre-book message that they will have to provide me with their email address in order for me to send them the rental agreement and I have not had any issues with using that option.

We have excellent credit.

No experience with that one in particular but I can tell you that you are on the right track. 

Would you run a credit report on the buyer?

Tying up a desperate and in arrears homeowner with a purchase contract you can not perform on and in which a sale will happen ONLY if you are successful flipping the property for a higher price can cause extensive damage to the homeowners finances, credit and personal life.  

I actually during the credit crisis when our PDX banks froze  ... contacted them about doing a subdivision A and D loan for me... sent docs down  but I got a pre qual letter to quick and what I thought was too easy... next step was the 10k for due diligence, being a lender myself it was just too easy...

With a non-recourse loan, you are not pledging your income, assets, or credit.