Excellent description John. I loved it.
I cannot speak on behalf of a professional mentor, considering I do not have enough experience to state a possible philosophy. I have, however, thought about this topic before; Saying that, I have some thoughts as to what I personally (other people learn may think otherwise) think a good mentor should consist of, from a student standpoint.
*Material should be presented in a simple manner, and then later into further detail. You should not overload students with intermediate information, otherwise students may get too confused easily.
*Showing through example I feel is an efficient way of learning. Programming for example, it may be wise to show the students the entire code, how its written (the basics of programming), and then another day try to have the students write their own code. With examples, students can see physically how to do something, and it may be easier to follow than verbally describing the steps in order to complete a task.
*Learning should be fun, I do agree, but to a certain extent. Many teachers that I have learned a lot of information from have been strict and on point with their schedules, but they make the material fun. With making learning fun, you can reach out to kids, as previously stated, and tell them the true importance of what the material is. Students may also intake information better if it the environment is exceptional. With solely lecturing information, students may get bored easily, and won't express the interest that mentors may desire.
These are my thoughts. This is just my perspective.