I'm not sure but I believe your blueberry seeds will be possible hermies again, especially if you grow in the same environment. 'Hermie made' seeds have a tendency to have hermie offspring BUT it is not always the case.

I believe that if your plant is stressed and male flowers begin to show later in flowering then the offspring are more likely to be feminized. But this time its with a lower possibility of them turning hermie.

I think true hermaphrodite plants are quite rare. It's more likely due to the strain or stressful conditions.

I believe your blueberry x cottoncandy is much more likely to be feminized. I would grow a few of these and take cuttings from the ones that tend to exhibit more of the cotton candy genetics.

Don't take any of this as gospel.