At first thought DSCR since the ADU will be a mid/long term rental, but those rates are most likely 9-12%.  

Time is running out Wife and 3 Children LIVE in the home and want to CONTINUE to live in the home as the Children are entering or in High School(a painful time to have to move or relocate for all) - YES lots of emotions all around involved.

My wife and I are looking to purchase our first property with hopes to turn it into a STR.

I've bought vacant properties through a judicial tax sale before but this is my first occupied property. 

Im trying to decide if flipping a home or buying a rental property is the best option for my first investment.

I agree with 100% with @Clayton SilvaA general tip: Spend time on income producing activities and ignore most of the rest. 

I am looking into that area as well because my son is moving there and I would like to have my own place to stay when I am there, especially if I get grandchildren any time soon.

The plan: I am identifying on/off market properties that are targets, will do all of the real estate work (listing, showing, advertising, vetting, etc) and will split the cost of the purchase of the home and the material costs for any needed repairs.The contractor will be subbing out portions of the job and be on site mostly full time until the project is completed. 

Once the fee is paid in essence the realtor loses the first position to do business with the client so if additional properties are to be purchased the realtor isn't guaranteed that business.

If someone was observing me all the time they would say I'm working all the time.