It's great that you're making Bailey's walks a family affair!
There's no reason why Bailey needs to walk behind anyone unless that's something that you really want to do. A well-behaved dog walks on a loose leash, without pulling, but the whole concept of being "alpha" by walking ahead of your dog is really a misconception.
No one needs to be in the lead, per se, but it will be easier to teach your pup not to pull if no one is ahead of the person holding the leash. Bailey would naturally try to catch up to whoever's in front and that would work against you. Keeping the group together or with the person holding the leash in front is going to be easiest as far as training goes. Lots of positive reinforcement for not pulling is going to work wonders, too, and stopping all forward movement any time the pup gets ahead will help Bailey realize that the only way to continue the walk is to stay with the people.
It's a good idea to have everyone participate in the training, as long as everyone does it the same way. Since you're walking as a family, you will probably be pretty consistent as a group (which benefits the pup considerably).
There are many ways to help establish leadership roles that just require patience and consistence. You can read up on this on my website (www.kippsdogs.com/tips.html
- go to "pack hierarchy" for ideas on building leadership). Everyone in the household should use the same rules and boundaries, and once leadership is amicably obtained, some rules and boundaries can be relaxed (depending on the temperament of your particular dog).
Melanie and the gang in Alaska