Aquatic Battler of Northrend

I used the 3-croc strategy for all trainers except Beegle Blastfuse, where I struggled a lot with the combination of strong flying pets and RNG. For him, I switched to a team of two of the slime pets from Nazjatar & Slim (from an Ahn'Kahet questline). In my case, I used

Slimy Fangtooth (Ooze Touch, Sewage Eruption, Moonfire)
Slimy Eel (Ooze Touch, Sewage Eruption, Moonfire)
Slim (Ooze Touch, Phase Shift, Nether Blast)

All the Nazjatar slime pets have the same moveset so you should be able to use any of them if you don't have specifically the fangtooth or the eel (that's slimy darkhunter, hermit crab, octopode, otter or sea slug, as well as the fangtooth or eel).

For Dinner I generally was able able to get up a sewage eruption, a moonfire and a single ooze touch before it killed my Fangtooth. Lift-off hits like a truck - he crit every time he cast it and nearly 1-shot my pet, so I had to reset a few times and hope that RNG would make him use Flock instead! Generally Sewage Eruption would kill Dinner the same round my Fangtooth died however.

For Gobbles, he'd reliably sleep my slimy eel the first round with Food Coma, but if he followed up with Gobble Strike i would be okay. Sewage Eruption->moonfire->ooze touch if i got a chance, if I didn't the sewage eruption would get him.

For Warble I just cast Nether Blast. Use phase shift after he casts Ice Tomb when it has 1 round left on the debuff on your Slim and you should dodge the stun and can finish him off with more nether blasts.

Aquatic Battler for Major Payne:

Terror Jelly 2-2-2
Toothy 1-1-2
Muckbreath 1-1-2

wish off the bat, spam waves until wish comes back up. His plant died and the mech was close. Then the two gators for the dumb bear, rip, bitw, and surge as a filler.

Beegle Blastfuse

Aquatic team

Slimy Fangtooth (1,1,2) - start with phase shift > Expunge > Ooze touch
Slime octopode (1,1,2) - Start with phase shift > Expunge > Ooze touch
Tragg the curious (Didn't use it) (2,1,2)