The calcium is high - that may be contributing to the seizure activity as calcium affects muscles and even a slight increase out of range can cause symptoms.
The BUN, creatinine, and especially the phosphorus levels indicate major kidney disfunction. A phophorus binder should be added to her diet.
The ALP/ALT indicate increased liver enzymes.
Dehydration will contribute to increased chemistry values as well as constipation due to fluid absorption thru the intestine - the IV fluids were definately needed. You may want to consider giving her fluids under the skin at home (the vet's office can teach you how). The fluid support will help the elimination of toxins.