Now a days most investors can't rely on the mls, therefore turn to wholesalers.

Don't rely on Zillows(ever).

The tenants are getting a bit restless - with numerous visits from inspection, appraisal, survey, plus however many visits from potential buyers prior to all this.What surprises me is the estoppel letter actually sounds like the lender is injecting itself into the lease by adding these terms to the letter the tenants are required to sign.I will not agree to any modifications of the Lease nor make any prepayments of rent without the prior written consent of LENDER.In the event I receive a notice from you stating that all future rents should be paid to you, I will comply with such notice without setoff as to any claims I make then (or in the future) against the Landlord (or any of its successors).I recognize that you are relying on this Certificate in making a loan to my Landlord (or its Successor).I hereby agree that the Lease be subordinated to any Mortgage from Landlord in favor of LENDER and all additional and or future advances, thereunder, and to any and all extensions, renewals and modifications thereof, and said LENDER shall be and is hereby agreed to be made prior, paramount and superior to any of my right, title, or interest as tenant under the Lease and I hereby agree to subordinate any and all of my rights under the Lease to LENDER.Is this usual and customary? 

You didn't rely on banks or your normal everyday financing.

I relied on excel spreadsheets to keep track of rent paid, then also had to enter income and expenses separately into quickbooks.  

Lenders will be relying on the current lease and the concerns mentioned in their debt coverage analysis regardless of what an appraiser may use to evaluate value, they are not related areas as one is to cash flow, the other to asset evaluation.

If it turns out that I'm happy with relying on a hopefully superior message via YL, I'll do YL. 

Thank you for the rely @elizabethc.

Because we are were all part time, we heavily relied on our contractors to take responsibility of getting the plans and executing and we went on our Mary way. 

I used to write checks directly to subs, but I can't scale myself, so I have to rely on GCs; otherwise I would spend all of my time on accounting and writing checks to subs.