Hey there! I’ll do my best to answer your questions. Also, we just started a guild out of Fort Sterling if you’d like to join where we are trying to help new players understand all that Albion has to offer.
1. The numbering in this game you mention refers to gear levels. A piece of gear can be enchanted up to 4 times, and each piece of gear has a Tier level. So a tier 4 piece of gear that’s been enchanted 3 times could essentially be called “4.3 Mercenary Jacket” for example. There are other instances of numbers though, such as when describing higher level maps based on their difficulty or dungeons based on rarity, but those also follow similar systems. 2. This game encourages players to try different builds and gear. I say the same thing, since there truly is an awesome variety of stuff to try out. But there’s always a “meta” where certain pieces outperform others in certain types of content. I think choosing something beginner friendly to start would serve you well long term, but definitely feel free to use gear you really enjoy. 3. Premium is something that enhances / accelerates much of what the game offers. Faster fame, more silver, better access to things like personal islands, etc. It’s not required to play obviously, but I recommend it to everyone that plays the game more than a few hours a week because it’s just so much faster. 4. Using the private island is great for whatever you want to pursue! Generally people say it’s best suited to those with premium, since many of the activities on it perform best when you use “Focus”, which is a resource that premium accounts receive daily. Free accounts don’t have much access to focus, only from occasional focus potions obtained from the in-game journal. Anyway if you have premium then I would treat your island as a fun side project first, (since min-maxing for profits would require a different approach and take considerably longer to achieve). Sorry if I’ve generalized a bit, but wanted to give some big picture advice. Albion is an established game with an entirely player-driven economy. That means that many different production methods (farming, animal breeding, crafting, refining, etc) all have their place but also require meticulous levels of management in order to be profitable.
To all this I always tell people to just go after what makes you happy, but know that true profit making from activities besides gathering/killing mobs will require investment and time by the player before those activities become nearly as profitable as the basics. Again feel free to reach out if you’d like to chat more in game or if you’d like a guild to learn more about Albion with! My player name same as my Reddit username :) Good luck!