The seller has agreed to carry up to 20% as a second note to cover the down payment, but I can not find a lender willing to go with that deal. 

I do this for any vendor I use each year, as I carry workmens comp on my properties for myself and workers I know aren't covered themselves. but if I can prove my vendors have insurance when I'm audited, so my insurance agency compute rates in my favor, because vendors had their own coverageAs far as lien waivers, it's good practice to have anyone that worked on the house sign they have been paid and a lien waiver is used for that. 

Also, can private money be used to cover closing costs?

The rent will cover the payment.

If you could show us more pictures of the entire area around the door we could better visualize what you're hoping for after its finished.

So should be able to get 80% LTV at around 24k) I will make sure that my cash flow will cover all LOC expenses. 

The items that I gave the info for have many many light emitting diodes, and are also behind an opaque white cover.

The snippets of the lease you mentioned are quite short and not enough to see if it will cover you to do the full investigation on the buyer of the business.  

Thanks for sharing the pictures too, before pictures always makes me shutter, but it turned out great!

That means their income would have to be high enough to cover both mortgages and still be under the 40 something percent DTI to qualify for a second mortgage.All that said, if they can do it, I say go for it!