What do you think the Entities of Pillars 2, 3, 4, and 5 looked like?

We saw the Titanic Infernal (pillar 1), briefly saw the 6th unnamed secondary multi-limbed Titanic Infernal (pillar 6), Hibachi Shinmon's Doppelgänger (pillar 7), and Raffles Doppelgänger. What do you think the giant Infernals and/ or Doppelgängers that we didn't see while Shinra was "asleep" looked like, and their abilities? I wish we would've at least got concept art of what these would have looked like.