Hello, @honeydue. I've been following your series on hero types with a lot of interest. Fresh and thorough. I really liked it.
Now that you get to this point, I'd like to comment.
I'm not going to choose a mentor hero from your list, as I would have a lot of difficulties. You've hit me right to the heart with everyone. You refer to characters from books and movies that I've been passionate about (movies don't always do justice to books or viceversa, but in this case, both movies and books are fantastic).
The Lord of the Rings, The Games of Hunger, the Harry Potter series are treasures for the imagination... and the imaginary.
A very curious case on the symbolic level within the list you propose is that of Gandalf (The Grey), especially as he opposes Saruman (The White). Gandalf stands in the middle way (his heroic reflection is Frodo, almost against his will from the daily hobbit). He bets on the force of modesty which inspires the choice of the path of the common good over the glory or power which drives men mad. He is also a smiling hero (his representation by Sir Ian McKellen is more than accurate), and that smile conveys both childish innocence and the burden of mischief.
Of course, beyond the symbolic level, as a work of characterization of the character, this "grey" is present in a somewhat more acidic and tragic way in Haymitch, a little more solemn and mischievous in Dumbledore, and more parody in Hagrid.
A very succulent topic, but I will not abuse the extension.
I am very grateful for the opportunity to read your text, @honeydue.