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.
[spoiler="Test"]Time to aim from nothing to 99%.
Against the same stationary target at ~1900 range.
BDK Bow - 2000 Range
156 - 255, 99 frames
773 - 872, 99 frames
1420 - 1520, 100 frames
~1.65 seconds.
Spirit Elven Long Bow - 2600 Range
1109 - 1188, 79 frames
1757 - 1835, 78 frames
2132 - 2211, 79 frames
~1.31 seconds.[/spoiler]