I assume the best way of doing this is catching in another pond when full of eggs so identification is easier??? Then transplanting into my pond. If no males are present, eggs become food for something..
I think there are other ways as well, but no expert on this am I, so wait for someone with experience to chime in on that. I believe you are correct though.
CC are cavity spawners, right? If I have a relatively clean bottom, wouldn't they pretty much stay with what I have stocked?
Yes, they should.