In the RE space, that's typically flipping & wholesaling.

For a more general philosophy on hospitality, especially if you are going into the higher end STR space I would recommend Four Seasons: The Story of a Business Philosophy by Isadore Sharp about the founding and development of the Four Seasons brand. 

If you find a separate habitable space, the ADU cost is significantly less.  

After owning the property for 1 week and putting in a lot of sweat equity, I've concluded that I want to keep the Inherited tenants based on the condition of their living space and the quality of the people, Knowing I want to keep them to save myself the headache of a  turnover and vacancy of a projected move out If I were to suddenly increase rents. 

How do 5-7 people share food space, kitchenware, cooking time, etc?

Who needs three stories so in the second picture you see the open veranda space on top. 

They run a customizable fund platform that many fund managers have started using in recent years.I'm not involved in the development space much, but a newer person can generally only offer so much to a more experienced person in this business. 

Have a warehouse currently for a business I do(I order pallets of items and resell) but getting tight on space.

My experience says that the smaller the industrial space the greater the demand. 

I think there’s some sort of option of to do a little refi on both house 1 and 2 and get the money needed to wipe out the line of credit(allowing for bigger flip opportunities, especially if I partner up with someone) and also renovating that garage space with the private investor as long as it is under 1000/month.