I will try to get a pic of the front soon, they are basically the same with the exception of it's dual brake cylinders.

The letter "N" designates new or replace the part during rebuild. More than likely it will be a dealer only item.

I've never removed that sleeve, so I cannot help you there. I use boat trailer grease on my pins. Mostly just to keep them from rusting.

The rear bearings clicked at low speeds, such as idling around a parking lot. At higher speeds they would grind like you described. The rear bearing are not replaceable (sealed bearing), you have to replace the whole hub assembly.