Hi! That's so great that you are going to give this little one a happy home!
I don't know what to advise you to do, but if it was me, I'd disregard what I was told to do and haul him to PetSmart anyway...but that's me.
I wouldn't allow him on the floor on a lead...but I don't do that with mine anyway. Instead, I'd plop him on a pad (to protect his feet) in a cart and push him around the store and watch him. I'd keep him interested and engaged but watch for 'distractions' to see what 'upsets' him. I'd watch his body language and what's happening around him...listening closely, too. I'd keep taking him everywhere possible to socialize him, but keep him a distance away and safe from harm until I had a good feel for what he is really like in a social setting. It could be that, once he is comfortable with you and his new life, his behavior may be considerably different from what others have seen from him. When he's with you, he'll be picking up the 'vibes' you're sending out...which is that he is loved and you are taking him with you for his and your pleasure...where in a temporary situation, the 'temporary' aspect...the 'vibes' from his life being 'temporary'...may have been something he was sensitive to.
I know this may sound a bit 'weird'...lol...but it has been my experience that animals pick up a lot from their owners in 'vibes'...which includes the animal's ability to 'read' faces, body language, etc. from humans.
I took 2 cats who were 'neurotic' according to their owner...and found the cats were cats and the owner was 'neurotic' wanting the cats to 'not' exhibit certain natural 'cat' behaviors. They changed after coming to live with me and having their normal cat behavior accepted without fuss.
I got Brody last May and except for the "he loves toys"...which is COMPLETELY TRUE...lol...everything else they 'knew' about him from having him since a little puppy was 'while he was with them' only...he is completely different from their description..."he doesn't like to ride in cars"...really? Are we talking about the same dog? 'Cuz THIS DOG won't even leave the truck until he's been INSIDE somewhere...THIS DOG will 'camp' by the truck until it moves with him inside...THIS DOG is jumping up and down ready to go at the sound of key tinkle...lol
I got Mia last August and was told "she won't wear a top knot" and "I put clothes on her but she doesn't like them"...well, she wears a top knot now and has for many months, and she not only LOVES CLOTHES, both she and Brody will fight you for them and fight against having them removed.
I truly believe in a lot of cases the animal's behavior mirrors the human's underlying desires, and so I am really interested in hearing how this pup does once he's with you!
