If you're worried about their leash behavior, I would recommend investing in some dog training lessons. They'll appreciate the structure and discipline, and it'll make your life easier because they won't be going insane on the leashes and pulling you in two directions while you try and pick up one of their shits.
Doesn't have to be fancy either, getting them to learn a few commands (such as "sit" and "heel") will get them to understand the value of listening and responding to you. It's not much of a time investment either, it's just about repetition and a few 15-30 minute blocks of training each week.