I'm sure they are elites but could be wrong. I bought the game this evening so will be aroundYes but if those strong mobs are still purple it's a bit pointless grinding on them. Purple = 5 levels higher than you. Unless you have stacked accuracy you'll be missing them a lot which is why it's taking you so long to kill them and to learn about them.
I played on my Sorceress this afternoon from lvl 16 to 29 no problems as i don't move on until the next mobs will only be red anymore. I learned the lesson from the Ranger fighting purple mobs all the time, it's too frustrating and ends up much slower.