The fact that their documentation is not clear and they are in a hurry to move is a big red flag.

Review the quality of the tenant base (do they have a history of paying on time, what were the original screening criteria, do they have applications on file).

If you ARE occupying, you'll need to be able to qualify using your income, employment history and DTI.

https://www.biggerpockets.com/...12 Frequently Asked Questions (And Answers) About DSCR Loanshttps://www.biggerpockets.com/...8 More Commonly Asked Questions and Answers to DSCR Loanshttps://www.biggerpockets.com/blog/eight-questions-and-answe...What Documents Do You Need for a DSCR Loan?

Document everything. 

You don't have to file "Trust" documents in order to hold a tenant security deposit in trust.

I am assuming I should only apply for one loan approval since pulling my credit score/history will lower my credit number. 

Take advantage of it, search old posts (learn from history), and read as much as possible because that's how you get unstuck and out of analysis paralysis. 

An example, a small down payment initially, but the note has now seasoned for 60 months with on time payments documented by a third party servicer.

This was also confirmed when I went there to submit the required documents, but they couldn't give me a proper timeline on when it would happen claiming that they were backed up.