Master Li

Master Li is located on the Timeless Isle and is the Celestial Tournament host and watches the Celestial Court from the sidelines. He tells you about the celestial pet tournament--to participate, you must have 30 pets at level 25.

He sells several items that cost [item=101529] which are the following:

[item=101771]: 3 [item=101529]

[item=102146]: 3 [item=101529]

[item=102145]: 3 [item=101529]

[item=102147]: 3 [item=101529]

[item=102095]: 3 [item=101529]

25 [item=86143]: 1 [item=101529]

[item=98114]: 1 [item=101529]

[item=101529] are awarded for winning the Celestial Tournament and it's weekly quest called The Celestial Tournament.

Note: To enter the tournament to start accumulating the coins, you must have 30 level 25 pets.

Now reduced to 15 pets at level 25.

Celestial Tournament One Shots x3 week1, x4 week2, thru wk 8 (used the same team multiple times by sharing pets on a different account or deliberately wiping on last celestial to test)
Note that cageable pets could be purchased from AH or shared with friends who already have a lvl 25.
I listed CAGEABLE alternatives, so that you can quickly buy or borrow the pets you need. Or, you know, hand over victory to a friend with a level 25 pet.
RNG is always there - this worked handily multiple times for us, if it doesn't for you - try again, you'll get it.

6 tests
Shademaster Kiryn: Restless Shadeling 121 (or Giant Bone Spider 121 CAGEABLE), Terrible Turnip 212 CAGEABLE (perfect counter), Anubisath Idol 211 CAGEABLE. DOT, then first ability nuke until dead. Seed, sons of the root, wave spam until dead. Finish with demolish.
Wise Mari: Gilnean Raven 121 (uncommon) CAGEABLE, or Lil' Bling, Mechanical Pandaren Dragonling 112 (uncommon) CAGEABLE , Any Mongoose 122 (or Viscidus Globule 212 CAGEABLE). Peck, Call Darkness, Nocturnal Strike, Call Darkness again asap if possible. Decoy, spam Breath until dead. Bite spam, avoid with dive. Don't forget survival when low.
Blingtron 4000: Any Strider (or Aqua Strider CAGEABLE 112), Panther Cub 212 (or Any Stone-upgraded cat 212 CAGEABLE), Fel Flame 111 (or Pandaren Fire Spirit 112 CAGEABLE). Water jet, Pump, Pump when his armor is gone, else jet til dead. Prowl, Pounce til dead. Immolate, Conflagrate when armor is gone, else Burn.

3 tests
Wrathion: Mojo 212 CAGEABLE, Anubisath Idol 121, third strong vs dragonkin. Swarm of flies, tongue lash spam, heal when undead immunity procs, tongue lash til dead. Crush spam, dodge bolt hit. Third should be mopping up (301+ speed helps to go first).
Chen Stormstout: Lil' Bling 211 CAGEABLE, Rabbit 121, Water Strider 112. Inflation, then Make it Rain. He drops even if you're stunned. I swap the rabbit in, eat his swarm which hurts, burrow, scratch but dodge when locust swarm comes off cooldown. Get as much damage in on Brewly with burrow and dodge use to avoid inebriate and barrel toss throw. Nuke with water jet, finish with Lil' Bling Make it Rain if needed.
Taran Zhu: Maggot (Mr. Grubbs 222 is CAGEABLE), Scourged Whelpling 211, Restless Shadeling 121 Consume, Sticky Goo after stun, Consume/Goo but try to save Burrow for his next stun, Consume/Goo until Li comes out, nuke him as much as possible try to burrow his spin kick. Took a while but I could often kill both Yen and Li with Mr. Grubbs. Bring in other undeads to finish off their team.

6 tests
Sully: Any frog, Mojo 212 CAGEABLE, any Moth (Imperial Moth 111 CAGEABLE), Gilnean Raven 221 CAGEABLE. Swarm of flies, Tongue lash until dead (get swarm up again before you drop). Cocoon burrow and nuke with your two fliers, Moth and Raven went very well even when frog died early to crits. Beat handily all 6 tests, 3 manned twice.
Dr. Ion Goldbloom: Sunreaver Micro-Sentry 211 CAGEABLE, Lil' Bling 211 CAGEABLE (x2)/ I two-manned this team all 6 tests, was close three times. Armor, Storm, Immolate, switch, Make it Rain, Inflation, then gift package if you can but make sure to get another make it rain off, finish with Sunreaver. Bring any mechanical (dots ideal) as your third if you're nervous.
Lorewalker Cho: Any Ooze Touch pet (Viscidus Globule 111 CAGEABLE), Mechanical Pandaren Dragonling 112 CAGEABLE, Anubisath Idol 111 CAGEABLE. Ooze Touch until dead, Decoy, Breath until dead but bomb Knowledge, Anubisath cleans up. Beat handily x6

Haven't lost a celestial fight yet in 8 weeks.
Xu-Fu: Tranquil Mechanical Yeti (uncommon) CAGEABLE 112 and Lil' Bling 211 CAGEABLE, Iron fist, Lightning storm, switch, Make it Rain, Inflation, finish with Yeti. 2 manned many times, but had Clockwork Gnome CAGEABLE 111 lose half health finishing once.
Zao: Skywisp Moth 212, Cogblade Raptor 211, Clockwork Gnome 111 (alive from Xu-Fu) Reckless strike, Cocoon strike, Call lightning, Swap to raptor, Exposed Wounds, Batter til dead (two manned all three times, but grab a second cogblade, or use Clockwork Gnome left from Xu-fu as back up).
Chi-Chi: Three Rapana Whelks 111, doable with 2 but my first two died once. Acidic Goo, Ooze Touch, Dive, then keep Acidic Goo up and Ooze touch spam, diving when able when Chi-Chi's Ethereal is up (uses it every time it's available/every third round). Even when I missed ALL THREE dives I still won. x5 tests
Yu'la: Solo'd with Clock'Em 112 Jab spam, dodge after Yu'la flies. Brought Pandaren Monk 211/Kun-Lai Runt 222 as back up.

(These two pets can kill Chi-Chi, Xu-Fu, Yu'la, and Zao with this combo if you want to heal up in between rounds Pandaren Water Spirit 122 CAGEABLE/Chrominius 212 CAGEABLE Geyser, Whirlpool, switch, Howl, Bite if not Chi-Chi, Surge.) Add any Curse of Doom (Lesser Voidcaller CAGEABLE) pet for Yu'la (Curse of Doom, switch, Geyser, Whirlpool, etc)