Jeff,I would suggest another questions/request for info to add to your due-diligence:    "have there been any claims reported to you, submitted to the Insurance carrier, or that you are aware of, during the past 5 years"I would also suggest that you request that they get the "Loss Runs" (report of claims) for the past 5 years from the current owner. 

If it hasn't been filed, don't submit it and get a second opinion. 

Ive submitted the Land on there website and all it says its " they will contact me in 2 business days but never get contacted.

Now of course for a new build, or a major remodel, you will have to get an Architect and an Engineered set of plans, and submit plans to the City and a Plan Check company.

I'm going to get their license number and do a lot of research before I submit my info.

But where I'm at you we are required to " have some type of buyer's brokerage agreement in place to even submit an offer.

He has already submitted an application through Zillow, and we have the contact number of his current home manager.Please let me know if it's still a good idea to ask the potential tenant for a recommendation letter from their current landlord, or if calling the manager would suffice.By the way, what should we do if the tenant has simply provided a friend’s number, and the friend pretends to be the landlord or property manager, or if he just make fake letter?

On Feb 24 they submitted to my credit report, and each month since. 

Been in communication with the mortgagor and even after submitting the trust doc, they say it's insufficient and want a grant deed, quit claim or probate document.

Would I need to submit my personal tax returns, along with those of my partner?