Solid chapter. The thing that interests me the most here is Jellal (and Oracion Seis) fighting August. If Jellal vs August is really going to happen, it could be a parallel of Rave Master where Seig Hart (a.k.a the original Jellal) fought that one really powerful mage for seven days straight. Granted, i doubt the 7 days will happen here but it is possible that Jellal vs August will parallel that.
I 100% doubt Irene is Knightwalker. Pretty sure Edolas has no way to get to Earthland anyway, since Mystogan used Anima to suck up all of the Edolas Magic into Earthland. It can't be future Erza either because then, why the fuck would Irene want to kill Erza? Kill your past self, you die too. This leaves us with two possible explanations: Irene is Erza's mother OR Erza is one of Irene's enchantments.
As crazy as it may seem, it may be the latter. Remember, Erza said she didn't have a last name and it was Jellal who gave her the last name "Scarlet". Why would Erza not have a last name? Even if her parents died when she was too young to remember them, someone would've taken her in and her last name would've been the last name of whoever raised her. But she never mentions being raised by someone else which does make you wonder. It could be like Mavis where Erza learned to take care of herself but she hasn't mentioned that. So maybe, Erza is Irene's enchantment, but on a whole different level than Juliet and Heine.
But then that means Irene can just reverse the enchantment to "kill" Erza. Fuck. So now, the mother-daughter theory makes more sense. And if Irene is Erza's mother, then it comes full circle, as then we would have seen all the parents of the main characters (Natsu and Igneel, Gray and Silver, Lucy and Jude, Wendy and Grandine, Happy and Carla's parents, Erza and Irene would complete the circle)