The Coordinated Move/Attack/Strike chain are pretty mandatory for any pokeman battler who doesn't get directly involved.
As for the nuts and bolts of actually preventing trainers from getting directly involved, I'd use the Code of Honor campaign quality.
I'm pretty sure that the Lancer's Lifetime Companion ability doesn't interact with the Exotic Partner special ability from Beastmaster. Lifetime Companion grants you a "mount as per the Animal Partner feat," but I don't think that the mount is an "Animal Partner" if I'm correctly reading Rules As Written.
So your actual Animal Partner, which you got from your feat, that would get the Exotic Partner weird type changes and XP bonuses, but your Lifetime Companion wouldn't - presumably it would be a Normal-Type. Maybe your Lifetime Companion is your Rattata. Maybe you are just really attached to that Rattata.
I really like Mister Andersen's idea. Your core Pokeman(s) are the one that are your Animal Partner(s), and your alternates and benchwarmers, the ones your don't pull out as often, those are Contacts.