I've never lived in Amsterdam, and actually prefer The Hague - but in general, NL is a pretty cool place to live. Just do not be fooled into believing everyone is oh-so tolerant - there are the same biases all over the world.

I am not certain how visa etc works, and if it was even possible for an American to open a CS. Just be aware that weed is not legal in NL either, and opening a CS means you will be dealing with organized crime. As for a restaurant - if you or anyone else is ever in The Hague, check out "Scallywags" (tea room) in the center (Het Lint). Richard is British and started with the best tea room ever - and expanded with a restaurant and bistro. So it is possible! It's one of the places where I just immediately feel happy.