The thing that really makes me think Caramel's not mink actually is the gray undertone on the legs. I've never seen a mink with that before. Mink tends to be a more solid, even coloring, while agouti based colors like cinnamon tend to look like a combination of several shades that get lighter or darker on various places on the rat.
Here is a picture of my cinnamon Fenn to show what I mean:

She's a very red cinnamon, but you can see that really pretty light gray showing through in her shoulder/leg area. Her whole tummy fades to gray (she's got white berky markings over that, which are hard to see, but they're there). You can also see that her hairs are made up of not one color hair but light hairs, dark hairs, and everything in between.
Here's another picture of my two cinnamon girlies together, both displaying that agouti fade-to-gray effect:

My mink girl Cinder, however, did *not* have that fade-to-gray.


Nice even coloring all the way down to her white stockings.
And my agouti girl, Chinchilla, did have it:

I always found that the easiest way to spot agouti based colors
