I think that's about right -- except that the 6 Plus would be discontinued when the 6S and 6S Plus are introduced. A 6C (whether plastic or metal) could not have only the features of the 5S. A 6C would have to support Apple Pay. It would not get Force Touch, which even the 6 does not have. A 6C would probably have most of the features of the 6, but stuffed into a 4" frame. It might be thicker than the 6, but thinner than the 5S.