You need to know what the property is producing and how much it costs to do it.

We purchased five houses last year, all of which are producing positive cash flow.

(Top producing Mortgage Broker here). 

Real Estate Investment Trusts (“REITs”) allow individual investors to invest in large-scale income producing real estate typically owned by a company.

However, in multifamily (5+ units) or other commercial investment real estate, the value of the property is based on the income the property produces.

Do permitting officials need to see a licensed contractor, architect, structural engineer, etc produced the blueprints?

And asking others to tell you how to do it, go in and ask KFC, Apple, Nike, the local top Dentist, really anyone in any industry who is leading, ask them to just give you everything to be top producer too, see how well that goes.

In addition to what a normal wall takes to build wall rated for sound is typically double rocked with brackets with rubber feet screwed into studs that attach to horizontal track for the drywall, sound dampening insulation, any electrical will need to be reworked into boxes that extend that far, then sound caulk all the way around the edges of the wall and electrical boxes.

bah - I just hang 1/4" rock right over the existing.

As @Dawn Anastasi says, you need to turn over a lot of rocks to find a good lender.