Looks pretty complete to me. I am not so sure the other players realize the danger yet (except Germany sure does.) Unless the Archduke has a backstab for Japan waiting (after swallowing me since I border Germany's recent conquest), I don't see how anyone but Japan wins this. Land units are necessary on a water map (to an extent), but having a large early ocean going navy (with frigates in mass) means land units become xp to level up frigates to +1 range. In a truly competitive mp game, the Venetian Arsenal would be banned on a water map where production is scare compared to the other map types. Another important factor to consider is Japan's coastal bonus. Good luck defending against mass produced naval units that get STRONGER when they attack coastal cities (and most if not all cities are going to be coastal in this type of setup.
Global lurker 
; played in Civ VI PBEM 4, 5, 15; DL suboptimal Civ VI PBEM 17
; played in Civ VI PBEM 4, 5, 15; DL suboptimal Civ VI PBEM 17