1. sasuke doesn't have the stamina to be as fast as lee for long, kakashi said that during his fight with gaara.

2. they are alone because half of the villages ninja's are dead since the attack, they can't spare a jounin for a b rank mission right now and still be able to do all their A rank missions.

3. I didn't mind the episode it'a not gonna progress the story any but it could be an ok side story as long as it doesn't go more than 3-4 episodes, anything more than that and it's gonna be dragging.