That she ate heartily is very good news, a very good sign.
With the multi-symptom nature of this emergency in mind, I should have said "Not totally confident of a good outcome." And: "Many times, all-out intervention turns the tide." And even then, they are hard to pull back from the brink, if that's what is actually happening. Can't tell for sure without medical tests.
It's true that supplemental water can fix her problem if dehydration is the only cause (sometimes it can only ultimately be cured with sub-q injections of fluids, which you can do at home if necessary). It's worth going all-out with it. There is no down-side, and you can tell it's helping if her urates turn snow-white again. BTW, the simple plastic 3cc syringe is available at pharmacies and only costs a buck.