Very nice article. Well written and bringing a lot of clarity for people wanting to understand agility better.
Yet, I think you misunderstood the concept of MVP.
An MVP is meant for learning. It should trigger the "Build-Measure-Learn" loop. An MVP is therefore also reducing uncertainty as we learn on the go thanks to it.
Whereas an MMP (Minimum Marketable Product) is the sum of features you need in order to start selling your product.
Here is a good read for it: http://theleanstartup.com/principles
In the context of your example, the tiny house your grandpa has been building would be an MMP. As it is a first "finished" product.
A first MVP could have been the plans of the house.
Hope it helps :-)