I think that Musk will not have to sell Twitter because he already has enough other sources of income and such amounts will be negligible for him. He just does it as a hobby. Here in Australia, we also have many different opportunities to do our favorite things without leaving home, for example, I use the site spinline login which allows me to play different games without leaving home.

How does this resolve if he sells a minority stake to another investor?

What if he takes the company public but retains majority ownership?