Legs are rank 8 and yes, you do want to get the 2 piece from the blue PvP set. You can do this by matching any two pieces of legs/shoulders/chest depending on what other pieces you have. Another leg alternative that you didnt mention is legguards of the fallen crusader from BWL. You only want to use cloudkeeper when the cd is up.
Edit: Ignore this post, didn't read you were on PvE server.