I, personally, feel that for this to function well or better, the Knights of Malinor should not be just a militaristic order. I feel it should encompass a variety of things; like the art of writing, formal representation to certain events (when deemed by the High Prince/Council), attain and uphold a certain level of chivalry, a library, self-provided sustenance, a sense of glory and honor, and finally, a strict process for outsiders to join the order. One of the most important, I feel, is the strict process for joining the order. As they say, "One bad apple spoils the bunch." If the requirements for the entrance are weak and/or insufficient to this order, then, there is a chance a being of a corrupt nature will introduce his/herself into the order, and mayhap rise to power. If said corrupted person does rise to power, or even if they do not, they could poorly represent the princedom of Malinor, and disgrace the Elven race. As you mentioned, there would be 6 trials to gain entrance, which, with enough development, would root out and unwanted/undesirable individuals, and keep the order pure and clean. These are just a few of my idea for how to run the order, if it ever does appear.
-Private Cirdan Tiwele