I think you misunderstood me. While it can be purely stylistic in the modern interpretation, the element replicated must have some functional purpose in the original. I do not think that you have to reimplement the functionality, that was just the example I used.
Your examples are skeumorphic because they use functional aspects of the original. "Find My Friends" is not skeumorphic because even if such a thing as "Find My Friends" existed in a previous form, the leather has nothing to do with its function.
If that sounds confusing to you, then I don't know what else to say. You're wrong?
Almost all aspects of a physical object are "functional", so this is a strange distinction to make.
For example, the rich Corinthian leather of a desk calendar functions as an arm rest and also functions as a binding mechanism for the calendar pages within. The stitching of said leather functions to hold the piece together.
The point is that you do not need rich Corinthian leather to make a desk calendar; in fact the vast majority of desk calendars in the world do not have any leather on them at all. Even on the real-world object, the choice to use leather serves a decorative purpose--it is not a functional necessity. Yet I've never heard someone call a leather desk calendar "skeuomorphic."
But is it necessary? That's an important part of the definition. For instance, the wood on Newsstand doesn't make it skeumorphic, but the bookshelf design does.
And again, where is the original product design for Find My Friends? Why did I never hear about anyone using a leather-bound location diviner before?
Your examples are skeumorphic because they use functional aspects of the original. "Find My Friends" is not skeumorphic because even if such a thing as "Find My Friends" existed in a previous form, the leather has nothing to do with its function.
If that sounds confusing to you, then I don't know what else to say. You're wrong?