wanted to ask this question again -did vet do a pre and post bile acid test to rule out liver shunt as very common in yorkies and can cause seizures. It seems your baby had the seizures before and someone took the pup to a rescue which is sad
Please do this test as it is a fast of 12 hours then a blood pull then feed the pup and then wait 2 hrs then re-pull the blood to see how the liver is functioning and check the dog food protein you are feeding as high protein food can trigger seizures in a liver shunt dog - the liver shunt can be repaired and you need to rule this out before doing pheno - pleae this is very important - many vets are not familiar with this disease - join this group
Liver_Shunt_And_MVD_Support@yahoogroups.com as they are awesome at liver disease, kidney, and everything as they are very good at looking up info and very familiar with seizures and may give you some more info - hang in there ;(