Well that is the question: Does online casinos need a permit to operate?
Is this even a question?
Yes, you need a license to operate in a country, it doesn't matter where your business is based or if you have a presence there, there is always confusion about thinking online means you don't need to answer to the said laws, in reality, the things pretty simple, you interact with a client in a country, you provide this guy with a service, so in order to do so you have to have a license to provide this service in the said country!
Nothing can be more clear then looking at casinos and their license in Europe and realizing some are banned in Spain and Germany while operating in France, while some banned in France are operating in Spain, although both are based in the UK.
As for your other questions, for real up to date answers as information from March might be already outdated, you need to consult a lawyer, the only one I can answer is the second one, as again it doesn't matter where you operate let's say Suriname, it matters to whom you offer those services, so if you have Japanese clients you need to above the laws there and get a license there!