New Poodle: Shy Nature

Question
I just picked out a standard poodle at 6 months of age from a remaining litter of 3--he was friendly but a bit more reserved than other 2 poodles.  He hid for a few minutes prior to coming out to greet us, but warmed up within 5 minutes (whereas the other 2 bounded out!)  We chose him and found his slightly more quiet nature charming.  Now, at 1 week later, he is incredibly bonded to our family (me in particular).  He won't leave the house to urinate without one of us with him.  If I go in one direction, he is right there with me--he explores, but only minimally.  We got an electric fence and it almost isn't necessary if we are in the yard, there is no way this dog will leave our sides!  If a new toy is given to him, he is more into "us" than the toy.  He retrieves things briefly, but is more into us than the toy.  An umbrella was opened by our trainer, and he wouldn't go near it until I touched it.  The trainer expressed concern.

With kids, at the bus stop, his tail is down initially and he hangs close to us.  With 1-2 minutes of time, he eases up and they can pet him, but they come to him (not vice versa).  He is very afraid of most other dogs.  He will visibly tremble in their midst and lean heavily into me.

I suspect these are not good signs (I've read enough), and as much as I hate to admit it, I am thinking of returning the poodle, as it is only 1 week (heartbreaking though).  We are a family of 5 and want a pet that can work with our life (lots of other kids around, lots of dogs around)

Your input appreciated, but I think I suspect I know what I'm going to do.  He is adorable to us!  

Answer
Returning a dog is a tough decision.  I see many questions where somebody has bonded to a dog that isn't right for them and don't want to return it.  Some dogs never recover from a lack of socialization in their first 12 weeks.  There are those that claim they can fix any problem, and certainly most problems can be reduced.  Still, that dog could mature into a fear biter.  

Returning the dog may also help the breeder to understand the importance of proper socialization and making sure the demand is there before breeding.  What are they doing still with 3 puppies at 6 months?  They should have been in their homes being socialized to their environment at 7-8 weeks.  Check the other 2 carefully too.  Although fine with a visitor, they might not do well with a crowd or traffic, perhaps panicking when the bus comes.