Jake here, and TVShowsonDVD.com has leaked the back-cover of the Book 3, Volume 4 DVD!  It includes titles for all the four finale episodes.  So what are they?  Here they are (highlight to see):

318: Sozin's Comet, Part 1: The Phoenix King
319: Sozin's Comet, Part 2: The Old Masters
320: Sozin's Comet, Part 3: Into the Inferno
321: Sozin's Comet, Part 4: Avatar Aang

So, it looks like Ozai will be "Phoenix King" and not "Phoenix Lord."  Hmm.  Oh well, I guess it seems less lazy.

Why didn't we release the finale titles ourselves?  Well, first of all the entire staff is not currently working at Nickelodeon, so that makes it a tad harder to get information.   I actually had 319 and 321 before, but didn't have 100% confirmation, so it would have been stupid to just release them.

Personally, I was hoping "Into the Inferno" was not a title for a finale episode, as that is exteremely lame and not an "Avatar title."  But who am I to second guess the writers?

Of course we have known they would all begin with "Sozin's Comet, Part" as revealed earlier.

To view the back of the DVD cover, click the link above or go here.

Thanks to Yoshi from DF Chat for the heads-up here!