You need to differentiate "ingame" unique voicelines and other media. For ingame they will have unique voicelines for the region they join or for their own storyline. This also will follow their canon classes.
Eve: Join during altera, so has altera voicelines.
Add: His story started in elder but in the background, thats why he has his own unique voicelines.
Rose: she was teleported to altas at the start, thats why she has voicelines there.
Elesis: Officially join the party at velder, she (and i quote) "train and command the Velder Knights stationed at Feita". So technically she didnt fight Durahan Knight, Amethyst, or Berthe.
Topic on User talk:FlareKyn
From Elwiki
I'll rephrase it. They will only have unique voicelines if they are part of the Elsword & Co. storyline.
For Eve case, those voicelines before Altera Core is already explained in her trivia. She visits those locations during the before joining quest.
Elesis only has voicelines in Velder because thats where she join the party and are part of the main storyline. We should wait for her before join side quest to find out more about her before Velder or if she fought any boss in Fieta.
Add shadows the main cast, so he is technically part of the main storyline.
Rose follows the old before revamp story. As she appeared in Altas during the old story, they just added unique voicelines and therefore its just there.
The unique voicelines are also tied to the canon path, so your argument about Crimson Avenger is already wrong.
