Here’s a visually pleasing arrangement of the provided colors, taking into account contrast and harmony:

1. #C7A978 - A soft, muted golden tan (lightest).
2. #7C7C7C - A neutral gray.
3. #751A35 - A deep, rich crimson.
4. #382B22 - A dark brownish shade.
5. #252514 - A very dark olive green (darkest).

This arrangement transitions from light to dark, creating a balanced and harmonious flow.

If you would like this in a JSON format or have any further requests, feel free to ask!