Diamond accidentally leaked the December solicitations before the comic book companies got a chance. They've since been taken down but other sites snagged some of the info.
Bleeding Cool has the info here on 2 in 1.
As he hinted earlier on his blog, Jim Cheung will be the artist.
MARVEL TWO-IN-ONE #1 LEG
(W) Chip Zdarsky (A/CA) Jim Cheung
The Fate of the Four Part 1
THE FOUR ARE NO MORE, SO TWO MUST DO! Something is very wrong with THE HUMAN TORCH and only THE THING can help him! It’s the Marvel Universe reunion you’ve all been waiting for (well, HALF of it, at least!). Plus: What monumental secret has DOOM been hiding since the end of SECRET WARS, and how will it completely change the lives of Johnny Storm and Ben Grimm? PLUS: Includes 3 bonus MARVEL PRIMER PAGES!
In Shops: Dec 13, 2017
This interview states that the main focus of at least the first story is Johnny and Ben trying to find the rest of the family. Doom holds secrets. I'll follow the title for a while. Maybe it'll be good although I've never heard of this writer. Cheung is always good.
The primer pages? Well, that put's it over the top!