Let's talk about Hunts - a detailed rundown of their assumed mechanics

[Leknaat]

The "unconfirmed" status are things I have personally not verified...

Kaiser Behemoth - Approach spawn points with Behemoth Heir minion out.
Bird of Paradise - Has a chance of being spawned each time Squonk does the move "Chirp".
Senmurv - Complete the FATE "Cerfs' Up" 5 times in a row.
Gandarewa - [unconfirmed] seems to be related to the gathering of items from Legendary/Folklore nodes
The Pale Rider - [unconfirmed] treasure maps?
Leucrotta - Kill 50 Allagan Chimera, 50 Meracydian Voivre, and 50 Lesser Hydra after the window opens.

Unrelated, here's some spawn maps I have generated, some of which may be interesting (like Kaiser Behemoth vs. the A Ranks). I use the "Composite" map for finding B ranks.

http://cablemonkey.us/huntmap/

KB - can be flying and still pop it as long as the heir has been summoned ala Nandi.
Bird of Paradise - Squonk doesn't even need to be killed
Pale rider is definitely opening the chest to Wyvernskin Maps in hinterlands (I can't confirm leve boxes)

Cerf's up has a horrible RNG to actually come up. It's about 15 mins to 2 hours to pop and it USUALLY takes about 1.5-2 hours per instance of the fate unless people are actively clearing fates in the zone.

I think there might also be a 'within 1 hour' clause to 150 Leucrotta mobs but I can't confirm this since it's really hard to tell when Leucrotta really opens. I killed all 150 at like 122 hours in for Leucrotta it took 1 hour 20 mins and couldn't get a spawn so either it wasn't open or there's a 1 hour time limit like Yarukiba suggested in a previous post. Finally decided to go back at 144 hours, had some help so we barely squeaked in 150 in 1 hour.

Given how hard Gandrewa is to pop there might be something that's not being accounted for. For me it's mindlessly gathering collectibles from both nodes till he pops. Maybe it just is repeated gathers. The last Gandrewa that popped I was the only one gathering and I went from I think... ore > heaven > ore pop. No chains (had a couple you obtain nothings, but always got at least 1 gather each time)... yeah baffling. I also waited till around 134-135 hours. :<