lord of the rings - Did Saruman copy from Radagast?

Probably not.

master of shapes and changes of hue

Let's look at what the Oxford English Dictionary has to say about the word "hue" (and remembering that Tolkien worked on the staff of the dictionary, which makes this a valid reference):

http://www.oed.com/search?searchType=dictionary&q=hue&_searchBtn=Search

Of these, definition 1 appears to be the most relevant here, and is the earliest attested (971) so let's have a look:

...Form, shape, figure; appearance, aspect; species.

Unfortunately the fuller definition is behind a login screen, but it goes on to derive "colour" from the more primitive forms. However, this being Tolkien, when we read it context: "master of shapes and changes of hue" - it seems obvious that "changes of hue" here probably does not refer to colour - Radagast may be a shape-changer!

This is discussed further here (which also notes: hue from Old English hīew, hiw "form, appearance, color") - Christopher Tolkien's own speculation (noted in the just given link):

Can this have been suggested by by Beorn's acquaintance with Radagast?

Is sourced from HoME 7, The Council of Elrond (1), note 27.

(As an interesting aside, the 3 occurrances of the word "hue" in the Silmarillion all relate to colour, so the question of what exactly Tolkien did mean here must remain open.)