get NifSkope and open the bridge. you'll notice some nodes attached to several parts of the bridge.
IIRC, those nodes are named. what you call on the script is the name of the node. if you want to change the position of a character, set it in a node, then offset it manually.
the animations are also relative to those nodes. if you open an animation (say, Picard's entry animation), you won't see it right in front of your eyes, but to the right part of the bridge, then it will walk down to the captain's chair and then sit down.
what I mean, is that if you rotate your view, you won't rotate around the animated character, but around a 0,0,0 of coordinates that is equal to the 0,0,0 of the bridge model.
if you want to add yet another character beside those already added in the stock bridge, you'll probably have to edit the bridge itself to add a new node.