Furthermore, take note of how every name is simple, and not longer than four letters. That's because they needed names that could fit within the four-character limit from the original!
Unfortunately, this trend was broken with the group's fifth member, Sophia... which in its own way is appropriate. Final Fantasy I only had four party members. Sophia, being the fifth party member, breaks this rule, so of course her name will also break the naming convention.
Before Dissidia there's no hint given of the Warriors of Light's actual personalities, reasons for taking on the quest to help the world nor of they're even from that world, so they may have been Jack, Jed & Ash all this time but this is the first time we're seeing the "real origin".
Though the second trailer seems to strongly imply that they're actually the predecessors to the Warriors of Light in the original game, especially with the emphasis on them having dark clothing. Given that the story seems to be angling itself as a Protagonist Journey to Villain arc, they could very well be a proto-Warriors of Darkness paving the way for their successors to finish what they and Garland started.
Frank Sinatra's "My Way", which is utilized in the final trailer and the ending credits, is strangely appropriate, considering Jack's propensity for aggressiveness and triumphalism. Yup, the lyrics that invoke those two themes are the spark for the song's infamous reputation in the Philippines as "the killer song".
The game seemingly subverts the prophecy of the four Warriors of Light when Sophia joins the party, resulting in a group of five. However, the prophecy was fabricated by the Lufenians, and actually refers to their own agents ("Strangers") who were sent to Cornelia to play the role of Warriors of Light. So when it's later established that Neon is native to Cornelia, rather than being a Stranger like the other four, it makes perfect sense.
The technology that the party uses, including a whole cellphone, and their modern attire seem massively anachronistic. Besides Neon being a native Cornelian, who notably stands out from the other four, the others are all Strangers with advanced Lufenian technology and trends dumped into a genuinely medieval world.
Sophia at first seems like They Wasted a Perfectly Good Character... but then the ending which reveals Jack's friends are in fact the Four Fiends means that she went on to play an incredibly large role after she became Tiamat, destroying the Lufenian's society and killing most of them while driving the remaining ones into exile as revenge for the Lufenians putting all of Cornelia into a time loop for their own selfish purposes. Tiamat is also the Climax Boss of the original game thus giving Sophia a main role.
Regarding Different Future's ending : While the role as God of Discord removes Jack from being directly able to watch over and protect Cornelia, the power of his Godhood would allow him to create enough conflict to have a version of his original gambit play out without him needing to personally self sacrifice. On top of that as his direct opposite will be a Warrior of Light , potentially the one from Cornelia, they can protect their multiverse of Final Fantasy from such tragedies as the cycle that Lufeanians established or anything like Dissida from ever happening.
Jack and his party are radically different from the Warrior of Light we knew from Dissidia. Given how said Warrior was known for being caught in a time loop in his battles against Garland, what exactly awaits Jack and his friends here?
The Multiple Endings of the A Different Future DLC allows you to either set the stage for Dissidia or go along with Jack's original plan. As such, the Garland in Dissidia may well be a different one if Jack goes along with his plan and not the Moogle's.
What exactly set Jack on his innate need to kill Chaos? It's not to save the land, it's not for revenge, and it's not known yet what Chaos has exactly done other than exist. Have the Powers That Be cursed him to force him to be a hero? The trailer already questions if the party we see is really meant to be the Warriors of Light according to prophecy.
With the second trailer revealing Jack's full name to be Jack Garland, his mysterious and corrupting dark crystal powers make sense if we take Dissidia Final Fantasy as canon: as a Tyke Bomb, he's effectively already channeling the origin of his abilities that will go on to define him as Chaos.
The Old World of Cornelia was a valuable resource to the Lufenians, but still separate from their true seat of power that described as, "beyond time and space." While Jack is successful in severing the Lufenians from Cornelia, slaughtering assets positioned in the Old World, and interferes with their ability to reboot the planet: somewhere in the multiverse is the greater Lufenian empire.
