i would rule out liver shunt before epilepsy since liver shunt runs in this breed more than epilepsy so make sure this is ruled out. Have a blood panel done as with alot of fleas they can get anemic as well which can be a problem in a tiny dog like this so have the blood checked. If you can fast for 12 hrs and do a pre and post bile acid test with her being so tiny i really think this is liver shunt not epilepsy
You are an angel to care for this little girl. Keep us posted but keep in mind alot of vets are not real up on liver shunt so you need to push for testing on this asap. What are you feeding and did this seizure happen after eating? Was it a grand mal where she was thrashing or petit mal where she was stiff on side sounds like since you heard the noise it was grand mal. DO NOT LET THEM GIVE HER PHENO OR POTASSIUM BROMIDE WITHOUT TESTING FOR LIVER SHUNT