Patch 2.3 introduces a change where if you mouse over a corpse it'll tell you which character can loot it, if there's loot you can't see (such as quest items) so that you can skin/whatever
The high end cloths need primals, but not primals made only by alchemists. Alchemists can transmute from one type of primal into another on their daily cooldown but they need 1 kind to make another. All of the primals needed to make the cloths themselves can be gathered from mobs in the form of motes. Alchemists make Primal Might, which combines a bunch of the primals into 1 might (ie, fire, air, water, nature, etc) The Primal Mights are used for lots of things: http://www.wowhead.com/?item=23571