The only real estate invest certification is your deals history and the money in your bank account.

Often times ESA is just a phrase tossed around because many people bank on the fact you may not be well versed on the law enough to realize this and they assume once the declare their animal is ESA you will not pursue the matter further (though you should). 

I have heard rumors that some smaller banks may consider it on a case by case basis.

For longer term financing (not hard money) I would look at small portfolio lender banks. 

I have been receiving Section 8 rents direct deposit to my bank account for past 3 years, and sending PM rent information.

What will banks require?

They usually require being renewed every 5 or 10 years and the bank can close your line at any time.  

Create the seller financed piece as a $50k second lien mortgage at an agreed upon rate, and explain that you’ll pay down the $50k note to them (which they’ll be earning interest on) and after a year or two (when you can shore up your credit/income requirements) you’ll get everything refinanced into one loan so that the seller and the original lender are paid out.He’ll collect interest on his $50k before being cashed out in the future, and you won’t have to go through a bank.

Banks do not have a choice on this number with this loan type.

Try Republic bank, local privately owned.