The nav station seems to have been rendered obsolete by the 24th century. Remember that on the Enterprise D, the 2 forward stations were Helm and Con. Voyager's bridge design had the Con station in the rear, on the opposite side with Security.
No, they were conn (meaning helm) and ops (meaning ship operations). On TNG, Data was the operations manager and manned the ops station; on VGR, Harry Kim held that post.
It's only on TOS that there were separate helm and navigation stations. In all the 24th-century shows and Enterprise
, they were combined into the single conn station (though I think it was called the helm station in ENT).