^^^

1. No you don't need specific amounts of points for anything, they are just there so you can have some slight customization to your character. As far as what stats do what, this page on lodestone gives a nice rundown of what stats do. I'd take a look at the play guide on lodestone if you have any more newbie questions since it's actually well done now, but don't be afraid to ask about stuff on the forums too.

As for Archer stats, STR (Physical Damage boost) and DEX (Accuracy, boost to Archer's damage) are fine, but I'd recommend putting some points into PIE at some point. PIE increases Archer's damage, magic evasion, and enfeebling potency. The last of those makes it more likely for your added effects to land (Like the Bind effect of Shadowbind, the Blind effect of Gloom Arrow, etc) and can prove quite useful when you can more confidently rely on these effects sticking.

2. You currently can't reset stats, but I'm guessing we will be able to this coming patch next week. For now don't worry about where you put your stats too much. They are a nice boost but not too significant, and STR and DEX are useful for ARC anyway. As long as you avoid INT and MND, you should be fine.

3. All we know for now is that we need 30 Archer to unlock Bard, with a new Bard quest every 5 levels after that. Keep in mind that Bard is not separate from Archer. Bard is essentially a more specialized mode for large party play, and you can swap between Archer and Bard at will as the situation arises. Archer will be more useful for solo and small parties.