Gnomeregan's New Guardians

Level 25 blue quality Shore Crab is your best friend for this. It's a little time consuming, but, if you keep up Renewing Mists and Shell Shield and attack with Surge you should be able to get through almost all of the fights using nothing more than this aquatic friend.

I was able to get all the way to the Bloated Leper Rat with blue level 25 team of Shore Crab, Fishy and Left Shark. I only used the shark once as the Shore Crab and Fishy were able to take out everything.

For the Leper Rat fight I used:

Unborn Val'kyr - Curse of Doom, Haunt
Zandalari Anklerender - Black Claw, Primal Cry, Hunting Party
Sharptalon Hatchling - Falcosaur Swarm, Predatory Strike

~~~~~~~

Gnomeregan Guard Wolf, Gnomeregan Guard Mechanostrider and Gnomeregan Guard Tiger:

Amalgam of Destruction - Immolate, Fire Shield, Flame Jet (Fire Shield is your best friend for these three fights)
Blazehound - Obsidian Bite, Frenzy, Puppies of the Flame
Dark Phoenix Hatchling - Burn, Immolate, Conflagrate

~~~~~~~

Pulverizer Bot MK 6001:

Lil Bling - Inflation, Extra Plating, Make It Rain
Stormstruck Beaver - Jolt, Lightning Shield, Discharge
Direbeak Hatchling - Falcosaur Swarm!, Ironskin, Predatory Strike

Using Inflation with your Bling and then Lightning Shield with the Beaver should be all you need to do. Those two attacks should kill the MK 6001 without any issue =)

Good luck, have fun and don't forget your pet bandages ^_^

Crabs didn't go well against first boss since it's Mechanical. I used:
Electrified Razortooth (2,1,2)
Ruby Droplet (2,2,2)
Had Living Sandling (1,1,1) as a backup, didn't use

For 3 elemental bosses after that I used crabs with Elemental attacks
Hermit Crab (1,1,2) - did particularly well, taking first two and a half pets in each battle consistently. Priorities: Stoneskin > Whirlpool
Emperor Crab (2,1,1)
Moonshell Crab (2,1,1)

Stage 3 - Door Control:
Mudshell Conch (1,1,1)
Hermit Crab (1,1,1)
Had Emperor Crab as a backup
Snail team might work here well

Stage 5:

Cockroach:
Chrominus (1,1,2) - not ideal, but worked for 1.5 pets
Direbeak Hatchling (1,2,1)
Bloodgazer Hatchling (1,1,1)

For Leper Rat I changed Chrominus specs:
Chrominus (1,1,1)
Direbeak Hatchling (1,2,1)
Bloodgazer Hatchling (1,1,1)

Stage 6 Bloated Leper Rat
Rabbits worked well: Dodge -> Stampede -> Flurry
Elfin Rabbit(2,2,2)
Rabbit (2,2,2)
Alpine Chipmunk (1,2,2)
When Rat dies it kills active pet with it. If you can't kill it with first two rabbits then swap out second one before it's dead

Stage 7 Mechanicals:
Electrified Razortooth (2,1,2)
Thornclaw Broodling (1,1,1) - not ideal against Undead, try a Rabbit here
Stormstruck Beaver (2,2,1)
Lightning Shield is a key here against mechanicals, but don't use it on first turn

Stage 8
Lightning Shield team:
Electrified Razortooth (2,1,2)
Thundertail Flapper (2,2,1)
Stormstruck Beaver (2,2,1)

You have to turn in the quest to Micro Zoox outside the dungeon for some reason. So just use him to teleport out after you defeat the final boss.