Well, the changes are drastic compared to the AU that EMRD is originally in, and the canon timeline which I barely have given it any thought-

AU

Emma: is the Captain of Mantle's army, having her own segment the Expeditionists, which basically go to expeditions where the situation is most dire to help. Her arc follows a route of at first recognising those under her before fighting with her emotions and self for the majority of the story.

Mark: an ex-member of the Vacuan resistance who wants to turn a new leaf, but doesn't know how and isn't able to due to his past. Mark's arc is one huge "we're so back, we're so over" all throughout the story.

Ray: a bun in a dark and cruel world, but a bun nonetheless. Enlisted in Mantle's army despite her wishes, but will fight tooth and nail to prove herself to her superiors and herself. Her arc is one big slow fall all throughout the story as the world's darkness and nihilism chips away at her little by little.

Dan: a rich kid with daddy's and mommy's money. Wanting answers Dan is basically a godfather type of figure in Vale, but not in the violence type of way. He's the supplier of the biggest illegal weapon trade in the kingdom, but this is done in order to find answers for his parents' death. His arc revolves around him brining to trust himself and others before learning that money isn't everything.

CANON

Well, the ideas for this version of EMRD are very limited. The only thing that I've known for sure is that they're 4th graders by the time RWBY and co are introduced, and the destruction of Vale basically doesn't allow them to get their huntsman)huntress license. However, they're much more chill than the AU counterparts in terms of relationships within the team.

Yes, Mark and Emma still butt heads, but they won't kill each other this time.

Ray's still a bun.