Pack leader and walking issues

Hi there, so I have a 5 month old Dane x and a 6 year old Shar Pei. Now before I got the pup I was the pack leader, as far as my Pei was concerned, but a few months after getting my puppy I noticed something. While my Pei still sees me as the boss - although he now often gets distracted and doesn't listen - the puppy doesn't. I don't know why, because he should have learned from Boris (the Pei) that I'm the boss. Comrade (the puppy) listens to me in a one-on-one setting, but as soon as he even hears Boris shake (he wears a choker and it jingles) his attention is gone. I'm trying to teach this pup how to walk on a lead and because Boris has no leash manners and is so distracting to Comrade I leave him at home, but Comrade still doesn't listen to me as he can hear Boris calling him all the way around the block. He constantly pulls because he's so interested in everything, and sometimes he even turns around to try and go back the way we came. I'm not sure how to fix this dominance issue or the leash training issue, so any advice would be greatly appreciated.
Regards,
James Holmes.