When I designed the plugin, I had considered it would be way more intuitive for users to track the slots on their own with editor variables, rather than having an abstract array most of non-programmer developers might be confused about how it work. Besides, there's times when you generate a copy or instance at some point, and only add it long after that.
But I can work something out, like adding an optional parameter to the generation commands to immediately add the generated actor, if that covers the need you ask for. Would it work for you?