I was thinking about this from the perspective of a juggler, so for an example a beanbag or a DX ball is made specifically for juggling, therefore cat 2. A soccer ball on the other hand, was made for soccer, therefore cat 1. Not sure what do do with objects that "are not made" such as stones, nuts or fruit. For now, I think they are cat 1 as well.
I think actually the diabolo had the function of a whistle from the beginning. But the diabolo we use today would be cat 2.
I love the name EBLIBI! I will suggest it to Ameron. I do not think a separate category is needed, since it still falls under the categorization of objects modified for juggling. One could of course think about subcategories.