I was just rereading Marineford when I found something interesting. In a flashbasck, Ace told Little Oars Jr. that he had made the straw hats in Wano Kuni. Ace had been in Wano! That probably means that the other WB's had been in Wano as well.
Ace could have met Kinemon and Kinemon would have taught Ace the arts of Foxfire. Now that makes Ace's abilities a lot awesomer.
Anyways, if the whole WB crew had been in Wano, I really wonder what they did there and what impressions they had left.