This zone can be completed by a raid of level 50s, and quite quickly. The last named is a 40 x2, you must clear a bunch of grays to get to the only named, that as of 2015/09/14, dropped wood (Level 45 Adept, possibly drops T5 masters, and a rare)
There are two non-attackable NPC groups on the west and east side of the beaches, you must clear the heroic encounters around them for these NPCs to become attackable; they are both 38 x2 with heroic-epic adds. Once they become attackable, go ahead and kill them.
As of 2015/09/14, no 'remains' spawned at all, only the final NPC. We got no messages about these NPCs casting any sort of conjuring or do anything other than become killable. After killing these NPCs, and the final named spawned.
*OUTDATED AS OF 2015/09/14* Watch your game messages carefully. At some point after killing the lizards around these NPCs, a message will appear and refer to the remains of an old foe that they are trying to conjure. *OUTDATED AS OF 2015/09/14*
These messages and events did not occur. We waited several minutes (10 minutes from after clearing the east/temple Soultaker), there were no particle effects, animations, or messages about a conjuration. Nothing happened after killing the Soultaker and Spiritcaller.
(The foe being conjured is a level 38^^^x2 skeleton (Asogwe Greths remains) that spawns when their conjuration is complete. When the skeleton spawns, the soulstealers become attackable 38^^^x2 mobs as well. A second name can be found also on the other side of the jungle/grass area off the beach, Soonogs remains (38x2).)
No remains ever spawned, the skeletons stayed as non-attackable NPCs the entire time after they popped, when the Soultaker and Spiritcaller each became attackable (2015/09/14)
Kill the protectors of fear.
When all the protectors are dead, an NPC in the middle of them will begin casting. Watch your game messages again for the message that the waters are rising in the lagoon. When you see this message, the NPC should become attackable, kill him quickly.
When the NPC casts the spell to raise the waters of the lagoon, Alizasaur the boss mob and two Protectors of Fear will come out of the water.
Get your wooden treasure box because T5 loot sucks.