One can never be too polite, right? I don’t know if there is an “official” set of rules on how to address people in Japan, but for first meetings and when you’re not sure, being polite will never offend anyone, so it’s a pretty safe strategy, I think.
If you go to Japan, this kind of thing is probably quickly picked up on. You’ll just have to observe the people around you and do what they do.
Besides, you don’t have to stress about something like this. Japanese people are people after all. Tell them that you’re still learning about politeness and how to address people and they will understand.
Sorry if that wasn’t what you wanted to hear, but it’s all I could contribute with.