First of all, a big thumbs up for a developer that is so involved, thank you.
To answer the question about rouges life leech, it is from skill number 8. I can confirm that it also doesn't work with my rogue. When I shoot with the life leech aura on, it does nothing. Even if I kill multiple monsters in 1 shot.
Can you range fire against enemies with a bow or mage while not having to click on them? Gameplay wise it is kind of annoying to always have to click on the target, instead of shooting in a curtain direction?
No, it will only increase the power of your spells (ice ball, ice ring...)