Maybe it will be an all-new combiner using the same connection ports? Energon Constructicon Maximus/Classics Devastator has not been around for quite a long time. I figure the reason the initial Crossfires were made because the Universe/ROTF Superion and Bruticus figures would be available in reasonable quantities by the time the upgrade sets were released.

edit: Also, it's probable Fansproject would know of TFC's own upcoming Devastator and avoid doing something with Energon/Classics Devastator themselves.