If you count Edo Tensei users as having whatever Edo Tensei DNA they need/they once had as valid, that means you must necessarily count Itachi's ownership of Shisui's eye, easily making him the top ninja on the list. After all, things you aquire outside are counted if Edo abilities are counted. If anything, Danzo should also be up there. Kotoamatsukami, as far as we know it, has the ability to make anyone do anything that the user wants. This could include just standing still and doing nothing or simply killing themselves theoretically. So, 1. Itachi get's shisui's eye if edo tensei users get previously acquired DNA, and 2. Depending on whether or not Itachi get's Kotoamatsukami, Danzo should in reality be 2nd or 1st.