Chinese herbal formula's may contain toxic ingredients, occasionally, but they are so well balanced that the formula's themselves are not toxic. There are a few toxic herbal formula's that are only used for a very brief period of time, and non-of these are for seizure disorders. Additionally, most formula's compounded in this country have removed the toxic ingredient and substituted a nontoxic ingredient.
Side effects can occur if the wrong formula is given for the patient.
All of the herbal formulas that your have listed should be fine for your rabbit. Use a half or quarter dose of the Gui Zhi Jia Shao Yao Tang.
Most formulas for seizures are very cooling formula's and may change the consistency of the stool adversely. And, of course, if there is any adverse reaction, stop and reevaluate.
As always, Chinese herbal medicine should be used only under veterinary supervision.