hi. i think if you don't feel like you are getting your expectations met then it might be best to move on, as if anything happens once you have your pup you could always question your choice regardless of whether the breeder is a reputable one or no (and KC assured is absolutely no guarantee of that), I have heard horror stories of 'kc assured breeder scheme' litters and the unsocialised fearful scrappy pups sold before they should leave their mum.
Neither is a schedule of vac's etc. as every breeder does things their own way but not all breeders do that from a point of the best for the pup/bitch.
Its unnerving to not be able to actually get to choose your pup until the end when they are due to leave, whether the litter is from a breeder wanting to keep to show or work or not. If the breeder is planning to keep a pup or two to run on, they won't decided til at least 4-6 weeks and yes, sometimes up to the 11th hour. Those breeding purely for selling on woudl probably have a different approach.
Unfortunately no breeder is qualified to assess peoples personalities! They can only best guess on their gut, or if they see something obvious that is reflective of a pattern, or the obvious ignorance of being around dogs, and how to treat them, but even then if you detect a keeness to do it right and to follow your own best efforts for your pups, and there are obvious differences that can be seen. Still there is no guarantee of anything, and some are better judges of people than others, but still wrong, so choosing each pup for the family might be going a bit way too far and a bit too up themselves
A pup and family choosing each other is such a wonderful part of the process.
Breeders that want to run on pups for further breeding/showing/working will tend to offer the more selfish approach of keeping all the prospective puppy owners waiting right till the end when they are sure of their own choice because that will take priority.