In the trials I've done, a limbus body part doesn't take on the properties of meat until it gets attached to a living, ensouled body. If it's cut off, it returns to being plant matter.

Since the ball isn't exactly meat, I don't know if it can or can't be used while it's inanimate. I have to assume not, just because this place seems to be intentionally making this as hard as possible.

But how much of a body is needed to put a soul in it? If I stuck a disembodied arm in the fountain, would that be enough? If so, could we do that to the ball?