I feel it's too soon to assume much about Walking Wake and Iron Leaves considering we don't have the full lore of Area Zero, the Terastal phenomenon, and the Paradox Pokemon yet, and the newly announced DLC is going to probably expand on that lore. I am sure Walking Wake and Iron Leaves will play a more major role in the DLC and also be a major component in explaining what the deal behind all of the Paradox Pokemon collectively speaking really is.
The fact that the drawings we saw of Iron Leaves and Walking Wake were stated in the book to be imagined is something I feel is a major major part in explaining what the deal behind Paradox Pokemon really is, and something the DLC will expand upon with those two in particular. The implication I believe is going to be the case is that the Paradox mons, all collectively speaking, come from the time machine that Professor Sada/Turo created, but the catch to them is that they are not actually from the past or the future that actually happened in the timeline, but rather they are fanfiction literally brought to life by the machine that is powered by Terastal energy in Area Zero.
As such, the fact that the drawings of Walking Wake/Iron Leaves is imagined is probably a major factor lore-wise, in that the Paradox Pokemon are in fact imagined to begin with and then the Terastal energy's powers brought what people of this era imagined to be ancient/future Pokemon to life in a way. So effectively, humans of the present era literally created Paradox Pokemon with their imaginations, and the time machine powered by Terastal energy manifested what human imaginations created and made them manifest as living beings. So Walking Wake and Iron Leaves aren't literally a Suicune or Virizion from the past or future, nor are they actually related to the beasts and musketeers/Swords of Justice we know today. They are what the writers of the Scarlet/Violet book imagined ancient/future legendaries to be like made manifest in physical form by the power of the Terastal energy and presumably the harbinger of the Terastal phenomenon, Terapagos, using a machine created by Sada/Turo.
I do think the DLC's storyline will greatly expand upon the lore of Area Zero, the Paradox Pokemon, Terastal, and the experiments Sada/Turo did, especially part 2 which focuses on Terapagos who is the implied Disk Pokemon. And I think the situation with the Paradox mons as a whole will become much more clear after that.