Re: Feeding a new juvenile
1. You want to give the snake some time to adjust, so I'd say maybe let it get used to it's enclosure for about a week before bothering it (other than the necessary maintenance: water changing, etc.)
2. I don't see why you wouldn't be able to feed in the enclosure. Personally I feel that feeding in a separate container would just add stress because they're being forced into a new environment and then having food forced on them. Feeding in the enclosure does not reinforce any aggression, and in my opinion is the best option for stress-free feeding.