1) Wish I could help you, its a mystery to me! I can tell you that the lining is usually (if not always) pressed meer. Like any pipe, I am sure there are duds and carved-mana-from-the-heavens...with but one meer lined having made its way through my stable, I can only report on it.
2) I had an older KBB Yello-bole meer lined that smoked wonderfully, especially considering I paid a whopping $0.37 for it...or at least it did after I removed the stinger, but thats another story. In the time that I had her in my active rotation, I found that she exhibited some of the qualities of meer (namely lack of stong ghosting), but seemed more...bullet-proof, for lack of a better term. I didn't feel like I was smoking a Faberge egg, like I do with my block meer. Finally, I noticed that it didn't seem to require as much resting time (which isn't to say that it doesn't require any) as briar; I could smoke three bowls per day, every day, without any detrimental effects rearing their heads.
3) I treated the pipe like a meer in the burning chamber - tip it and wipe it as soon as the smoke is finished; avoiding any cake. With cleaning, I would treat the pipe like a briar, allowing it to cool before breaking it down for a good swabbing. I would ensure that I was extra careful when cleaning out the airway that I didn't ram the pipe-cleaner too hard into the meer; I could see a pit developing over time if one wasn't careful. As I noted above, I found I could push this pipe without detrimental effects, making it a good choice as an all day (at work) smoker.
4) I'm sure others will have more and better advice to chime in with, but you're most welcome!