Sorry to hear about the seizures! Thyroid and seizures pretty much go hand in hand unfortunatly. I hear about them all too often since they're so common in Belgians.
Hopefully Molly adjusts to the meds and her seizures go away! With the correct dosage, the seizures should go away (unless it is not the thyroid that is causing the seizures, but at her age it's not likely to be genetic epilepsy).