In the middle ages in Islamic lands this is a difficult question to answer as we know far more about urban elites and intellectuals than we know about average people, sailors included.

That said, as far as I'm aware the answer, at least for the first question, seems to be yes. I would look the career of ibn Battuta, who, while his own travels were extraordinary, nonetheless didn't have to make any particular strain on a given leg of his journeys. A map of those travels can be found here. So it was certainly possible as a Syrian in the high middle ages to see Alexandria and Constantinople, if not necessarily Marseilles.