According to what we know, no. There are 10 trainer's ex in DRI, 5 of which belong to other trainers. This means Team Rocket could have 5 Pokémon ex. Only about half of 40 Team Rocket's Pokémon were revealed as well, so I think there's likely one more, something like Rhyperior or Nidoking.
I think you're reading too hard into this. The MEGA era is probably a mini one, so it could just import some leftover SV cards in their international release, should they not come in Destined Rivals or BW special set. I do share your opinion on what should have been though, the Trainer's...
75 is already Arven's Greedent too, so you know, no slot for the other 5 types (Grass gets 5 lul). I guess it is a pretty weird spread, but not much they can put in a half-set.
I kinda hate how the Trainer's Pokémon turns out to be mostly beautiful cards with mid gameplay, just because TPC already decided that they're going all in with Mega Evolution.
I think other than Dragapult, Festival Lead kinda struggles against Archaludon as well. This could get you the final 2 prizes, though I'm not sure if running this with 7 grass and SERetrieval is worth it.
Man, N's is already isn't doing good, and now they wanna take BB Cannon away from Zoroark against the little guys. On the bright side though, Wellspring is cooked.