Did quest 2 times, on Rogue (99) and Priest (98). Fast move skills (backslide/agi~up/relocation) are very usefull here, also i recomend to have any FAST RANGE skill/atack to check the mobs (stone~throw/insta~holylight/bow/etc). If you want to get all loots yourself - DON'T DO IT. Better go farm money for 1-2 hours (3-4+mil), buy the loots and say thx to vendor. Otherwise quest will become a huge waste of time. No offense, but quest is actually terrible. If you are not a rockhard person - DON'T GO FOR MYSTIC PET SCORE. When NPC says "Have fun" - it actually means "Get Rekt". For myself it was nothing but a torture (esspecially the "find~pee~in~the~ocean~x70~times" part). Better just go for Golden Peco, it isn't so much annoying. If you still are going for mystic one - GET TOTAL OF 9 MAX FOR EVERY NPC MOB, YOU DON'T NEED MORE.
Loots i farmed:
Fatty Chubby Earthworm ~ 1h
Earthworm the Dude ~ 1.5h
Talon ~ 1h
Harpy Talon/Feather ~ 30m
Peco Peco Feather ~ 30m
(you see right? it could be cheaper and faster if i bought just all the loots (yet something could be not on the market))
"Meanwhile" loots were sold with overcharge for 650.000 + i got Kukre Card and Clip.
Fatty Chubby Earthworm = 9, Earthworm the Dude = 10
Snake = 10 Anaconda = 23 (~1h)
Talon = 151, Harpy Talon = 151, Talon of Griffon = 1
Hode = 16 (+7 escaped; 30m), Argiope = 10 (+4 escaped; 50m)
Feather of Birds = 201, Feather = 201, Soft Feather =51
Peco Peco Feather = 201, Harpy Feather = 201, Cendrawashi Feather = 11
Swordfish = 12, Phen = 14 (4 deaths, lots of alt+f4, took ~1h)
Sidewinders = 11 (only 1 qmob on the map, are you serious? took ~50m)
970 points, 41 Bronse Coins from 24 Envelopes.
Fatty Chubby Earthworm = 1, Earthworm the Dude = 1
Snake = 5 Anaconda = 5
Talon = 100, Harpy Talon = 100, Talon of Griffon = 1
Hode = 5, Argiope = 5
Feather of Birds = 100, Feather = 100, Soft Feather =10
Peco Peco Feather = 100, Harpy Feather = 100, Cendrawashi Feather = 10
Swordfish = 5, Phen = 3
Sidewinders = 5
762 points, 34 Bronse Coins from 14 Envelopes.
(you can actually skip or go for lower numbers in npc mob parts if you are going for Golden Pet, you need only 550+ points to get it).