1 - A bow's "speed" is how fast it reloads, not how fast it aims. (Right?)
2 - Vivace increases aim speed (can't find where I posted the tests). Do other attack speed boosts, like the set effect, work as well?
3 - The range of a ranged weapon affects aiming speed. At the same distance, a higher-range bow will aim faster because aim time is scaled against the bow's max distance, not absolute distance to the target.