I like the labels you chose. It gives the map a definite modern, GPS mapping style and I think it fits with the clean style you drew the map in. And don't apologize about the English, the Guild is made up of people from all over the world and everyone is welcome
A couple, hopefully helpful, answer to your questions:
Since you labeled your water "Pacific Ocean" I would say that your labels for the directions (i.e. "north side," "east end," and "south end") fit with the orientation you depicted. For the "end" vs. "side" choice, I would just be consistent. I tend to notice that a location or city chooses to use one word or the other, but I rarely see both in one place (at least in the United States).
On the "port" or "harbour/harbor" question: a "harbour" is generally used for the sheltering of ships during bad weather or rough seas and is a natural or man-made area for the safe anchoring of a sea-going vessel, on the other hand, a "port" is a commercial docking area used for the import/export of goods and cargo but may not be a suitable location to anchor a ship. Although those are the general definitions, it gets a little tricky because a harbour can be a port, but a port can't be a harbour (most of the time). In the end, I would simply choose whichever word communicates the activities that happen at the location. This is my opinion, but I use "harbour" for anchoring of ships, safety, and mainly recreational boating, and I use "port" for commercial activity, shipping, and import/export.