Alright, I'm kind of confused by this statement, I think we're on the same page with it, but something is being lost. What I was suggesting is a third generic term to incorporate offspring of exactly Red's situation. Leaving the two lines as distinct for those who would want them distinct, but as lines of the generic form. While the generic form would be for uncertain lineage.
If you breed 2 lines of Pastel together for a super, then that super pastel breeds and the offspring are unable to be identified as one line or the other, what you have as Pastels, the generic term.
Also, Platty is just me throwing that up against the wall, I even said the name would need to come from the community and was using that as an example (a personally liked one, but I'm not that attached to it)