For our last single family residence we had a young married couple move in with a brother, all three applied.  

The ADU is a good idea for property maximization, but unless it has a separate driveway, it will push your rent in the main house down some because then you aren't renting a single-family house on a lot by itself.

He wants you to get deal under contract before he will even consider paying you a finders fee.

We are looking at a duplex first probably and then single family.

Even help with after you get your property with calls that help you manage the property manager!!

Quote from @Carson Hyland: Even if you buy the right property, failing to manage it well will kill your cash flow. 

BiggerPockets also has a calculator to analyze deals, and I highly recommend you start this as soon as possible, even if you are not ready to buy.

Recently closed a deal with a client that was a 3/1 single family house for $120k and they're renting it out to section 8 for $1550/mo!

I have built a few modular single family homes in Virginia using different manufactures. 

I love the idea and I would like to analyze deals using a variety of strategies and model each strategy out, however I am struggling when it comes to the rubber meeting the road for analyzing the deals.For example, I would like to analyze deals in a single spreadsheet for various strategies such as seller financing, subto, traditional lender, external investor, etc. etc.