Sure, but apart from that are CC allocated on basis of seniority, prior training in specific cabin classes, even cabin crew preference which may included cabin preference or preference to work with or not work with someone in the cabin crew cohort?
Additionally are F CC required to help out in the Y cabin?
If CC had free choice which cabin would they prefer?. Is F preferable over any other class?
Not crew but some of my best friends are ...
There is specific training by cabin class, and that largely dictates rostering.
Also on a two class aircraft the CSM would be in J and the CSS (deputy) in Y.
On a four class aircraft the CSM is usually still in J not F.
Typically only the CSM or CSS could choose to avoid someone.
Other crew could ask them but my friend would only entertain such a request if it suited him.
And what suited him was often either malicious or amusing.
In my experience it's more common for crew to help up rather than down.
So Y crew might help in J, rather than J crew help in Y.
Typically when clearing after meal service, or when J crew are on a break.
Crew preference varies: premium cabins can be easier, but require more meaningful interaction.
Throwing meal boxes at Y PAX can be easier, especially if you're hungover.
A lot of crew do prefer to be assigned to the galley during meal service to avoid dealing with PAX.
But it's not a free choice: see above.