Board Thread:Wiki Discussions/@comment-3422208-20140710042534/@comment-3279282-20140710105124

@Hell-Skull: No, but there's a big difference in burning things to create smoke (what Han does and what was done in the new chapter) and in burning water to create mist.

So, basically, if chakra that turns to smoke or steam is Futton, then Guy and Lee are Futton users, too.