Congrats on your new puppy and welcome to YT!
You seem to have the same issues I went through with my Oliver when I brought him home. I too got him at 8 weeks and the only problem I found was the extensive nipping and biting. This was due to bringing him home before he had time to fully socialize with his litter mates. The nipping does go away, you just have to keep disciplining him and say "no!" and giving him something he can chew on, then praise him for chewing on that.
As for the poo eating, haha Oliver did that too! It's most likely because their poo smells like their puppy kibble and so they think its food
If you put tiny pieces of pineapple in their food their is something about the smell of it that turns them off from eating it. I started adding bits of pineapple when Oliver was about 6 months so I would consult someone more knowledgable before feeding your 10 week old pineapple bits!
Good luck with your new baby!!!