Full Idea
The scheme of categories is very useful, and it might be that all that is needed are five general headings for beings - namely substance, quantity, quality, action or passion, and relation - with any formed by composition from those.
Gist of Idea
Have five categories - substance, quantity, quality, action/passion, relation - and their combinations
Source
Gottfried Leibniz (New Essays on Human Understanding [1704], 3.10)
Book Reference
Leibniz,Gottfried: 'New Essays on Human Understanding', ed/tr. Remnant/Bennett [CUP 1996], p.343
A Reaction
'Action or passion' as a single category sounds intriguing. He is very keen on active force in the world of physical objects, which presumably falls into this category. His plan sounds, initially, as good as any I have heard.