Kizaru could also play an important role assuming that he is indeed Vegapunk(a theory which I firmly believe). He could potentailly explain more about the Lunarians and their purpose, about Kaido's origins and such. There's also Queen being his former colleague(which could lead to a dramatic reveal)and his tech which is apparently "so advanced not even Vegapunk could replicate it", which is sure to pique his interest. Also, Kizaru did help Kuma help the SHs, further proving that his agenda isn't to really help the WG in their power-struggle. He's just using them at this point. So this could prove helpful down the line, maybe he would even be interested in Pluton's blueprints? Who knows. To add to that, he was the first one to volunteer to head towards Wano, and was seemingly the only one around other than Akainu who was actually available to set sail on a moment's notice, the only problem was the lack of intel. That being said, Ryo ties in to Wano and it would make a lot of sense...
