Seyn will have a Heel–Face Turn or will die (or both).
A piece of promotional art for Battlefront II shows only Iden, Gideon, and who appears to be Meeko. But no Seyn...When Admiral Versio forms Inferno Squad, Iden thinks about wanting to protect the young Seyn, but then shakes it off because she's a grown woman that can probably take care of herself. Foreshadowing?
Seyn is a Teen Genius/The Ace similar to Sabine as a Shadow Archetype of her, so either they can complete that by making Seyn die in combat for the Empire or turn her into a complete Foil/Expy by having her switch sides (but possibly fail to do so by dying in the process or being apprehended first). Either would just make Iden's grudge against the rebels even more personal.
- Confirmed in that she dies but has no change of heart.
