I know (or at least have a sense that) Reed Richards played a part in "Infinity" through his involvement in the Illuminati. Did any other members of the Fantastic Four play a part in that? Also, do the Fantastic Four have any significant part to play in "Inhumanity" and comics resulting from that? If yes, I may have to pick some of it up. If no, I would be a bit disappointed given the longstanding connection between them, the Inhumans and the FF that is.
The Fantastic Four weren’t really in INFINITY, they were still off on their interdimensional adventure. INHUMANITY isn’t an Event, it’s the status quo of the Marvel Universe, so there’s no real “part to play” for anybody per se. It’ll impact on FANTASTIC FOUR when and if those characters are back at a place where they’d be interacting with the Inhumans.