Welcome and congrats on your new baby at 6 weeks most yorkie babies has just started the weaning process from their moms and i help mine by soaking the kibble in warm water still soft since most don't have teeth until 5 wks or later
I sometimes give them baby rice cereal mixed with goats milk and i give them a dish of the goats milk cut 50/50 with warm water (i use canned goats milk from walmart) i hope this helps
listen to your vet he sounds very knowledgeable on the shots..some are not