You can't keep the staff and the scamps at the same time, except by not finishing the quest (or maybe a mod, but I don't know if one exists). Once you drop the staff, you can't pick it up again, and once you finish the quest, the scamps will stop following you. I don't remember if the staff disappears or not, but it really doesn't matter since it can't be picked up.
It's possible to finish the quest without actually dropping the staff (stuff it into a nearby corpse instead), but besides losing the scamps, you'll never be able to remove the staff from your inventory except by placing it into a container (can't display it, for example), and it'll disappear for good if you save while it's drawn.