One of the issues I have come across is the inspection cost for the building.

Or do you base terms on down and their credit application?

And, yes, I've paid that on properties I ended up not buying.

I need guidance as to where to even begin the due diligence on such a project. 

The only direct lender I know of that's willing to take a second position on a DSCR loan is Velocity Mortgage. https://www.velocitymortgage.com/The rates on these products are crazy though.  

i am seeking to rent out my single family house and am considering a property manager. what do you think i should look for in choosing one?

However if it is a smart deadbolt and a normal lock on the door handle they will need that key bc they will inevitably lock that one on accident and lock themselves out. 

I currently have a duplex with one side vacant and one side occupied and am looking for some advice about the current lease and the one that I hope to have signed soon!

Not sure if you have a direct question, but reading the questions between the lines on when a property is actually considered to be in service.Facts and circumstances.Generally for a rental property it is "in service" when it is "ready and available for rent" - meaning you are marketing it for rent, and a tenant could utilize a property that day.

Its a 2-unit property on Airbnb.