Thanks everybody!

Here are the macros for phase 3 Maly. On most characers I use:

/follow whoever
/target Malygos
/castsequence reset=target Flame Spike, Flame Spike, Engulf in Flames, Revivify

And then on 2 characters I have:

/follow whoever
/target [target=vehicle]
/castsequence reset=target Revivify, Revivify, Revivify, Revivify, Revivify, Life Burst

As long as you have a couple of minutes for phase 3, that's all that's needed. If you find yourself losing drakes in this stage, add more of the latter macro.