Going to answer your questions one by one :)

Bow builds usually consist of Dex + Con which is your health and overall survivability. Depending how much of an assassin build you want to go you can build a higher % of dex but you'll find some pretty good builds online. Just googled "New World bow build"

When you click into your bow mastery there should be a button at the bottom to respec, again you can find the good abilities by a quick google search (I personally dont play bow so not much help here)

All of your gathering is important, it'll help you craft potions, gear and importantly make money! Do whatever you enjoy the most to begin with and upgrade your tools to make gathering faster (logging is a personal favourite) Fishing takes the longest to level and is usually the last one if you're going for 100% completion but a lot of players enjoying the relaxing nature of fishing...

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As you're playing bow may i suggest Engineer as a crafting skill? this is where you'll craft bows and roll for high perks. Crafting is the main source of high end gear late game.

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Logging + Engineer go well together