Duke, you can hyperhydrate a dog throughout the entire keep, and towards the end, simply remove the excess fluid, and the dog will shed the excess weight without any issues. Dex, nor anything else, is needed. Pedialyte is used for electrolyte replacement, along with rehydration. Dogs don't lose electrolytes like we do, so that's just something else excessive that's not needed. If the dog was hyperhydrated throughout your keep, even at the end, there's no need to worry about deyhdration.
And no matter what we think about pedialyte, etc, NOTHING is just like using an IV except an IV. IV is basically assimilated when it hits the vein. That can't be said for anything that has to be drank or eaten.