I am not a psychopharmacologist or any kind of doctor, pharmacist or nurse. I can't answer your main question below. But I urge you to ask your question below to the appropriate doctor(s).

You wrote:

"So my question (for people here that know about meds): is there a mood stabilizer (that is not an antipsychotic, because those can trigger catatonia) thought to activate GABA that has a better safety profile than valproic acid."

I hope the answer to above is "yes". If so, discuss what they are with the doctor, if they can be prescribed to children (not all medications are approved for children), and if they may have a better side effect profile to Depakote.

Some people don't have side effects that others have on the same medication. Sometimes one just has to see what happens before condeming a medication. I know people who say they didn't gain weight on Depakote. I know others that gained a lot! I, personally, feel Depakote is a better idea for boys/men than girls/women because of the possible risk of Polycystic Ovary Syndrome to females, which is far from a given, to my knowledge.