The Maybar Endless Night  Festival is usually done the week before Halloween for 2 weeks normally, so this year should be no different.... 

 

Like all of the other festivals, you can start in a raid group, but must split when it comes to the opening of the cavern to defeat the dragon. 

One thing I can say is that the highest level toon should be the leader of the group and you must be in the same instance , group level and instance when entering into the graveyard in House J.   If you are not in the same instane then you can either exit at the gates of the graveyard or see Joe Lantern to switch instances, Maxmium  loot and drop will accure when everybody is in the same one. 

if there is a mixed group of different levels, you will get bumped to the lower level instance when you return back from defeating the dragon, so upon reentry into the graveyard, you will need to see Joe Lantern.

Example would be like Level 8 to 12 instance 1.  

Normally in a raid group the leader's level instance should be 1 level higher then what you are, seems to give the best drops for loot.

The Festival should be starting soon,  stay tuned for further developments as DDO makes more changes.

 

Patch 3 Update notes , pasted from the website ...

Of Special Note

Mabar Festival of Endless Night

• Monsters in Delera's Graveyard should no longer cast Meteor Swarm.

• If a Spectral Dragon fight fails due to an altar being destroyed, players will now get their Ethereal Keys returned.

• All monsters found in a level-banded instance of Delera's Graveyard now count as appropriate for rewards, as long as the character in the instance is not of a higher level than the instance's maximum level. This means that players who are in the appropriate level for the instance should no longer receive messaging that a creature is too low level to provide rewards. Players who are above the "level cap" of the instance will still get rewards when killing monsters that are within four levels of their character level, as before.

• Lich Dust and Vampire Fangs no longer drop from monsters in Delera's Graveyard. They can now only be obtained by trading in Motes to the Mote of Night Collector. The Mote cost to acquire Lich Dust and Vampire Fangs has been significantly reduced.

 

http://ddowiki.com/page/Mabar_Endless_Night_Festival  should give you more loot details and information