A definite concern, which is why I was "wondering" about it and not "I have been running it".
I am trying to deduce what I could add in to help. Note that Terrakion EX should be somewhat effective against those two decks on its own, and since it is just being teamed up with two Basic Pokémon, I should have room for more Items.
Since that is my planned Energy acceleration, I would also be focusing on basic Energy cards other than DCE. Terrakion EX can still OHKO an Altaria or Gabite and 2HKO a Garchomp, and without any Special Energy on it, Garchomp isn't slowing it down with Mach Cut. Bouffalant and Sigilyph are, of course,
dead weight in such matches, so it won't be easy. If I can squeeze in enough Hammers (already a plan to help Bouffalant) I think I can at least get it to an "even" match-up of tearing down the decks complicated set-up before it can reach "danger" levels.
Empoleon is the opposite; I would just have to hope I could successfully go toe-to-toe with it, literally keeping a light Bench. I guess in both cases, the deck would play like a weaker Quad Pokemon EX strategy. If it wasn't obvious for general readers, of course I am talking pure Theorymon here.