Sounds like you've got a lovely baby ball python, congrats on acquiring him/her. We leave ours all for a week or so to settle in and don't handle them much until we have two or three feedings in them. Afterwards of course they get the 48 hours of hands-off after each weekly feeding.

If you want to feed in a seperate container I don't think there's a really huge problem with it as long as you don't trigger a regurge when you are moving a just fed snake (or get bitten yourself if the snake is still in hunt mode) but there's also no real reason to do it. BP's are ambush hunters and tend to like hunting from their hides, from on top of their hides or using their hides as cover - very cool to watch by the way - so feeding them in their own enclosure gives them that. None of ours has ever mistaken us for rats - if they want to bite us, I'm sure it's because we deserved it LOL.

If you are really worried about aspen ingestion put down a pad of newspaper over it if you like but as Brad said, a tiny bit of aspen isn't a problem for a creature with stomach acid strong enough to fully digest bone, teeth, hair, etc.