Most albinos are Corydoras aeneus whereas your peppered cory is Corydoras paleatus--different species (not breeds). I'm no cory expert so others can help you with your question better, but I would guess the peppered cory is just hanging out with the albinos because they are meant to be in groups. Interspecies breeding isn't common, but it can happen. You would then get hybrids, probably infertile, but one never knows!
Female corydoras are larger, plumper looking than their male counterparts.