I too would leave him on the Royal Canin. Thats what Teaka came home with. I stuck with it for about 4 months or so. Yorkies bark unfortunately. Start training now. I know he is only 8 weeks old, but they're smart lil dogs. Find a word you like "Quiet" or "Shh" and say it. When he doesn't bark say "GOOD BOY!!!" (high pitched) and give him a tiny treat. Keep on doing this, a few times a day until all you have to say is, "Quiet!" and he'll stop barking. Now all I have to do is say "Teaka!" and she'll stop.
Try to have a routine. Go to bed the same time everyday. Play with him like crazy before bed. Then say "Bed Time" put a treat in his crate with him in it, and shut the door. He'll eventually get the hang of it. Patience is a virtue.
For the biting, get lots of toys. If he bites you, redirect it with a toy. I found that rubber toys satisfied Teaka better. Although now she hates them.
Welcome and good luck!