I may not be using the term "gain" properly...or maybe I am and I'm getting the valuation ratio wrong.

Take ownership of your mistake and learn to do the proper due diligence recommended above😊

Having rental history via a schedule E in your tax returns would help, but an executed lease agreement and proof of security deposit and/or rental income received should suffice. 

Take ownership of your mistake and learn to do the proper due diligence recommended above😊

In general I would say that if you are comfortable with bookkeeping, do a good job screening, you have a property in good condition, and you take the time to properly educate your tenant on communication and maintenance procedures, expectations of both parties, and responsibilities, you'll have no problem self managing 1 duplex on your own with very little time dedication.Typically you will probably spend 15-20 min a month on bookkeeping and entering transactions, and that is about it.

The question is, do you as an owner want to get the work done properly, quickly quickly, and efficiently, or are you more concerned with an itemized invoice?

for each deal they could make an 3 to 7k assignment.. with the proper backing they are making 20 to 30k per same lead by actually being a real real estate investor. what happens in many of these wholesaling / assigning contract hot spots is the competition as you state is fierce and people going around them  or they cant get it closed in time because they have no money etc.  

Looks like OP has a poorly done repair to a product that easily deteriorates when not properly installed or maintained.

Usually there are COO inspections that check for working and proper placement of smoke detectors.  

Proper Insurance has been a great partner for us, except, they will be dropping us due to high fire risk for our mountain cabin property.