I agree with your description of loyalty and duty! As for honor, I think it's having principles and beliefs and all that and sticking to it in and living life in a way that adheres to these, etc etc. For example, it would be so much easier to just kill all your enemies, but your honor dictates that mercy is a virtue worth upholding so you don't.

Often, duty and loyalty and honor get in the way of each other. In the army, I learned firsthand that duty will often make you do things to sully your honor. However, strictly adhering to duty is a form of keeping honor in itself!