Completed this (three successful runs) with a fairly well-balanced (if support-heavy) party of 6: SAM/WAR MNK/WAR (lv 56) WHM/BLM RDM/WHM BLM/WHM BRD/WHM We took the typical multi-enemy BCNM approach. Entered the BCNM, buffed up, healed to full MP. BLM used Elemental Seal + Sleepga II, and we proceeded to pick off the mobs one by one. We killed them in the following order: BRD > DRG > MNK > WHM. The wyvern remains after its owner is killed. On the first run, we saved the wyvern for last; on the other two runs, we killed the wyvern right after the DRG. Either way is fine; it doesn't pose much of a threat.