Often a bit testy, but probably normal. Depends on the individuals. Copy desk folks aren't usually recruited to fill in for slot unless there is an emergency. In news and features, it's pretty much the same people slotting all the time. Some rims help with slotting, though.
Designers are separate.
In sports, designers and rimmers rarely mix duties. Don't know for sure. Not many people leave, but when they do it's about 50-50 for other papers or other desks. Greatest strengths on features desk is the level of teamwork and positive energy. Working quickly on deadline.