The god dragons are all supposedly supposed to be on the same level as Acnologia, though I doubt any of them are actually stronger than Acnologia. Igneel was arguably on Acnologia's level as well, and Acnologia still emerged the victor of that fight. Rogue's future had Acnologia dominating the world, so there's that to consider too.
END's showings fluctuates. The version of END that fought Gray was meh. It was stalemated by Gray and stopped by Erza. It was basically on the same level as base Natsu with some degree of POF. END's power also seem to be triggered when Natsu that fought Mercphobia, but that version was stacked on top of Dragon Force and Ignia's flames was really what made it so powerful.
Touka is probably closer to Zeref's level, and not on the level of Acnologia. In a physical fight the version of END that fought Mercphobia would likely beat her. However, Touka's power seems to be messing with other people's minds and making them go out of control. I'm guessing that her role in the endgame is going to be to make Natsu go out of control, probably because she thinks she can use END's power to wipe out enemies with powerful magic. Obviously then Lucy will have the most motivation to bring Natsu back to his senses, so I'm actually expecting Lucy to play a big role in beating Touka.