Andy and the New Mayor - S3-E3
Visible crew/equipment: While Jess is up in the tree, the new mayor is attacked so he also starts climbing up the tree, then in the shot of the bear rushing toward the camera we can see the animal trainer who's behind the tree, as he releases the bear. (00:23:00)
Answer: It was a joke. They were supposed to be dumb hillbillies.
Both. According to later interviews with both Andy and the Dillards band (the real name of the band that played the parts of the Darling children, of which Charlene (Maggie Peterson - Mancuso was also a member) the reason the Darling boys never had any lines was because they would've had to have been paid if they spoke. In return for appearing without lines or pay, Andy promised to get as much of their music onto the show as possible which, he did. This obviously gave them a lot of exposure.