super easy with three falcosaur pets. I used snowfeather in first spot and did squawk, swarm and strike then swarm again that killed timbo and when he resurects second round of swarm hit finished timbo off. Pokey came in and i did squawk again, swarm snowfeather dies and then finished with rest of fight with above strat.
You really shouldn't pass in the undead phase, if you swarm in it you burn a tick of swarm so that you can get to a bigger hit faster. Find on many of these strats I kill it a few steps faster and safe for those reasons.
That didn't work for me (1st try and very close, but still) ... so I used the Snowfeather Hatchling (121) as first pet instead: Crouch -> Swarm -> Predatory Strike, afterwards use what is not on CD - it alone killed the first two and I finished the third one with the Direbeak.
Bloodgazer Hatchling was just spinning thumbs (all he has ;)
I was successful with an uncommon Mei Li Sparkler B/B, Royal Moth B/B and Blazing Firehawk. I followed the first part of the guide exactly and brought in the moth in place of the hatchling and on the undead round with Pokey I used Hawk Eye instead of passing. Then used alpha strike until moth died during Burly Jr's undead round. Didn't need Firehawk at all.