Crafting XP and your level carry over on every server.
That means you can have a character on all servers and all of them share the same XP bar. So it doesnt matter where you want to level up (you probably do PvE missions anyway, even on the PvP server). Its true, there is no risk when you play on the PvE server, but dont forget that the Santissima is one of the biggest and most expensive things in this game, so you will need to earn money to buy one on the server on which you plan to play on. I acutally think its faster to level up on the PvP server in a clan, because its much faster to do the missions in a group.
Yes at the moment, but it will change soon to 3 durability.
Everyone can have the same ships, your nationality you choose doesnt matter at all for that.
Not sure what that means, but everyone can buy/craft any ship (except some rare ships are harder to obtain, but those are only a few and Santissima is not one of those).
I would recommend you to join any nation you like on the PvP server and ask in the chat for a clan. Most of them can help you to understand the basics + leveling up together with you and are happy to get new members.
Corona Lisa's post in Game questions was marked as the answer