I have previously used the product to purchase an existing duplex.

In the meantime we want to be taking advantage of the great rates for existing mortgages. 

Typically this means they will take longer to close, may not have all the information of the companies they work with, and most hard money brokers get their money by taking an existing product and adding extra points to pay their fee.

A newly acquired building has storage units for each apartment unit in the basement. (12 units)  There is little to no mention of these spaces in existing rental agreements (from prior owner).

What constraints exist on your time/capital?

Any reputable RE attorney in your state probably has plenty of existing contracts for you to use.

I am from Norton, Virginia and am super appreciative that this site exists to give education, personal experience, and support to investors, new and old.

What potential challenges would exist on a broad spectrum? 

Does anyone know what banks refinance existing mortgage to a 1st lien HELOC on investment propertie(s) ?

Unsure of existence of asbestos wiring, lead paint - the interior seems to be plaster walls with hardwood floors.