I compared other properties in terms of age, sq ft, acres, beds, baths, basement, garage and a subjective measure of interior condition.I have a huge problem with the automated comps (Zillow, RPR, etc) because they could not account for the interior condition. 

The amount depends on negotiations between you and the property owner. 

The previous owner actually offered it to the tenant, which in turn, they reached out to me.

@Joel Oh What do you mean by: "Regular home owner's insurance will always pay for guest's damage to the house."?

They are empty (sorta) and the new owners (inheritance)need to cash out or create cash flow. 

A good tenant is more than just a rent check—they should respect your property, your rules, and the people around them.

The other way to satisfy is to get the property owner to refinance but that is not always in your control. 

Partnering with family and securing owner financing to acquire the property below asking price was a smart move, and the renovations sound like they added significant value.As a direct lender, I’d love to explore how we might assist with your future growth, especially as you look to scale into larger multi-family investments.

Does anyone know of a lender that will give a HELOC on an investment property.  

If the property is considered non-warrantable, you should still be able to do a standalone 2nd mortgage at 75-80% CLTV on an owner occupied nonqm 2nd mortgage.