For this to work, will I have to take the dual wielder feat and/or the two-weapon fighting style at lvl 4?
You don't need that so soon. You can take your ability improvements, if you like and have a high Dex. I would go with Dex and Char 16. You get at the last map in act 1 the gloves of dexterity, that set your Dex to 18. They are sold by a vendor.
You will already do a lot of damage, especially when you have your subclass and use slashing flourish ( ranged).
