I hope this doesn't sound too harsh but it sounds like you are trying to take the Yorkie out of him. I am really not sure why you got a Yorkie if you didn't want someone following you around the house and being with you every moment of the day. They are a pretty needy breed, meaning they love their people.
I would start over. Spend time with your pup, take time to walk him even if he isn't good at it. Get him socialized, even if you spend the time apologizing. Get him an expen, put his bed and potty etc. in that when you leave or can't keep him with you.
These little creatures are meant to be with their people. If you want him in a crate at night put it where he can see you and you can touch him.
In other words, ignore everything the trainer has said.
Too harsh? Sorry
