Quote from @Lolo Druff: Just like turn signals, you should always trust, but verify that the seller is telling the truth.Your offer to purchase should include a requirement that the Seller provide all documentation and agree to sign an estoppel certificate (also called an estoppel form or agreement).

Although you don't need licensing for many loans, it's probably a good idea to deal with and verify the licensing of NMLS licensed lenders.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Verifying last 2 years of rental history very important!

I would like to hear your thoughts and what I need to verify before making an official offer.

Given your extensive reviews and strong opinions about so many land investing courses, would you be willing to verify your identity as an independent investor?

Verifying last 2 years of rental history very important!

Assuming you meet real estate professional status (which it seems like you do - you'll just want to have a time log verifying) AND materially participate in your rentals, you simply wouldn't get that big of a year one benefit. 

., and ability to verify receipts and transactions (the verification is done by upper management to check and validate the revenues and expenses)4.

BTW I am a 10-99 contractor and have been focused on the rehab for the past several months, which affects my verifiable income.