It is annoying sometimes. I don't think you'll find a definitive authority on every issue. In terms of training and socialization, I disagree with your breeder and vet and instead look to what the expert vets who are board certified veterinary behaviorists have to say about it. And they say that puppy socialization is best achieved at a time before puppies are fully vaccinated, under certain circumstances. Here is their position statement:
http://www.avsabonline.org/avsabonli...ialization.pdf
As for feeding, I have always fed on a schedule of twice a day -- three times when they were small puppies. They poop at the same times, every day, so that makes indoor pottying easier for us to manage (we use pads indoors). I have heard stories of dogs choking to death on kibble when their owners weren't home, and I'm a worrier so I wouldn't leave food out. It also would not work well in my multi-dog, household and doggie pack dynamic (one is a bully!).
Good luck w/ your new pup!