Don't know about other desks. Each desk is understaffed. Very few editors do copy editing exclusively. Most also do layout or content editing, too. Only on news desk are there people who do only rim.
Most copy editors are lifers.
Career path is to get used up and move on. I know of is a slot who is now an assistant city editor in Broward. For the most part, yes, although our needs and hardships are given only token recognition by the bosses. In business, relationship is fine, although some frustrations about space limitations in the paper. Respectful and sometimes even chummy, depending on the relationship the individual editors have developed with the assigning desk.