Alright, Stormblood is only a few days away - let's bring up all the notes we have for the HW S Ranks, shall we?
I will keep Vandesaan's formating if that's okay.
So .. let's go:
Zone: Coerthas Western Highlands
Hunt target: Kaiser Behemoth
Spawn condition: Spawned by running or flying over or near the spawn locations with your "Behemoth Heir"-minion out.
Respawn cooldown: approx. 80 hours
Maximum respawn time: approx. 135 hours
Respawn cooldown after maintenance: approx. 60 hours / insufficient data
Maximum respawn time after maintenance: yet tbd / insufficient data
Zone: The Sea of Clouds
Hunt target: Bird of Paradise
Spawn condition: Squonk's "Chirp" will bring Bird of Paradise to show up. It doesn't matter if Squonk is at critical HP or not. If you are searching for Squonk: He will only spawn in the southern half of the Map.
Respawn cooldown: approx. 80 hours
Maximum respawn time: approx. 135 hours
Respawn cooldown after maintenance: approx. 60 hours / insufficient data
Maximum respawn time after maintenance: yet tbd / insufficient data
Zone: The Dravanian Forelands
Hunt target: Senmurv
Spawn condition: Spawned by completing the F.A.T.E. "Cerf's Up" (located at X:19.5 Y:27.5) five times in a row. It doesn't matter if you do it alone or in a group. Remember that the timer for the F.A.T.E. to respawn can vary from 30 minutes to nearly 3 hours.
Respawn cooldown: approx. 80 hours
Maximum respawn time: approx. 140 hours
Respawn cooldown after maintenance: approx. 60 hours / insufficient data
Maximum respawn time after maintenance: yet tbd / insufficient data
Zone: The Churning Mists
Hunt target: Gandarewa
Spawn condition: Spawned by gathering "Seventh Heaven" (located around X:18 Y:36.5 at 4a.m./4p.m.) or "Arumn Regis Ore" (located around X:10 Y:36 at 2a.m./2p.m.). Since these are legendary nodes you need the dravanian mining/botany folklore. You can get these for 99 blue gatherer marks in Idyllshire respectivly.
Respawn cooldown: approx. 90 hours
Maximum respawn time: approx. 150 hours
Respawn cooldown after maintenance: approx. 60 hours / insufficient data
Maximum respawn time after maintenance: yet tbd / insufficient data
Zone: The Dravanian Hinterlands
Hunt target: The Pale Rider
Spawn condition: Spawned by opening a Wyvern Skin Treasure Chest or a Levequest Treasure Chest (spawning through levequest chests seem rare. haven't seen this myself yet, just going by messages from otheres here. need more confirmation).
Respawn cooldown: approx. 85 hours
Maximum respawn time: approx. 150 hours
Respawn cooldown after maintenance: approx. 60 hours / insufficient data
Maximum respawn time after maintenance: yet tbd / insufficient data
Zone: Azys Lla
Hunt target: Leucrotta
Spawn condition: Spawned by killing 50 Lesser Hydra (located around X:12.5 Y:33.5), 50 Meracydian Vouivre (located around X:10.5 Y:37.5) and 50 Allagan Chimera (located around X:31.5 Y:8.5). (If it appears to be less that only means that someone else already killed a few when the window opened.)
Respawn cooldown: approx. 90 hours
Maximum respawn time: approx. 140 hours
Respawn cooldown after maintenance: approx. 60 hours / insufficient data
Maximum respawn time after maintenance: yet tbd / insufficient data
I will still look through my notes if I missed anything but this should be all from my side now.
Yes, the respawns after maintenance are approx. the same though they vary only in a small way. usually they open at the same time but, depending on the random factor, can take longer.