The respawn timer I witnessed was 25 minutes.
Like all Jinyu rares, he has a couple of nasty abilities that you need to watch out for:
Rain Dance: Keep moving till the cast has complete! It's a oneshotter.
Torrent: Interrupt if you can. Else it also kills.
Apart from that, try and keep your health up and you're fine. I did it in Guardian spec with the free pvp gear.
The Hollow Reed is actually a blue water strider pet called Aqua Strider and as of patch 5.03 bind on pick-up: