It's been fought over for literally decades and while it was recently given a stamp of approval by the necessary agencies, funding is in question and lawsuits are all but guaranteed.  

I would think the bank has no guarantee you will pay down the HELOC with the money and must count it against your debt.  

Start with a 100% or 70% guaranteed return.  

What kind of financing are you securing that allows all funds for downpayment to be borrowed without the guarantee from someone else?

They said that the LLC needed 2 years of tax returns, and I’d still have to sign a personal guarantee.

This makes them feel comfortable that guaranteed income should be coming from one unit you're renting out)

I guaranteed the investor a 15% return on their investment and we would split the profit after that. 

Point being - just remember an unused HELOC is not a guaranteed source of funds. 

I guarantee it's never their driver's license that they're holding and no legitimate lender would ever do that.  

They guaranteed on the letter: Provider’s phone, fax and email on their letterhead License number Provider is from the same state as you reside Attorney drafted letters for full compliance and effectiveness Provider’s signature You and your Animal’s information within the letter So as a Landlord, how will YOU verify a letter like this?