Well, really, there is only one big Tip. Don't Dance in P1.
I saw Oriniwen's post, and just had to publish this diagram (not to mention I'm in an MS Paint mood today).
If you keep Heigan on the corner, and the ranged goes to the opposite corner, you can outrange his spell cast time increase aura for Phase One.
Phase Two is still the same, so everyone still has to dance (this is not a magical-instawin exploit), but your Phase One DPS will be higher. W-a-y higher. And your hunter's pets won't die in P1, leaving them to drop their insta-rez for the second P1 (in which you can easily kill him).
Notes on Executing it: As long as tanks and DPS are on the raised part (even on the slant), they'll be safe. Ranged will need to give themselves a little extra time to run to the beginning of the dance floor for P2