Well as expected Luffy defeated Kaido in this chapter(1049)
with Oda probably reserving 1050 for reactions / celebrations
Also since Oda already gave a way for Luffy to overcome the strongest magma attack seen yet with higher lvl of haki, it kinda makes the elemental part of Akainu's powers kinda redundant. Another reason why I think it makes more sense for Sabo to be the one to finish him