Question for Object Oriented Ontology

What is your stance on the reality of universals?

This is motivated by the thought that if all that exists are objects, then there are various classes of things that are not objects.  E.g., numbers.  If they are objects, they must be objects in a very difference sense.

Moreover, if all that exists, exists in an object, then there is more to being itself than objects.  For example, per Levi Bryant, objects would have powers that are not independent of objects.  Avoiding the fallacy of simple location, we need not say that a power is strictly in a single object--if I understand Levi right that is his view--but there is something more basic to objective being than objects.  What then is the reality of each?  Does a flat ontology, for those among OO who insist upon it, mean that there is only one modality of reality, i.e., substance qua object?  In Levi's case, that doesn't seem true.