Being present in a masters set or equivalent does not mean the character is still alive in the current timeline. Example: Urza was printed in Modern Horizons 1, a masters set a couple years ago. Urza was last seen alive like 20+ years ago. Apocalypse, june 2001 at least, maybe a set or two afterwards.
They most likely included Dynaheir and Firkraag and company by similar logic. They are there for fanservice and name recognition.
This isn't a Masters set, but it's true of the OG Commander Legends set too.
PS
Lae'zel is going in straight into my Serra and Master of the Flowers (Planeswalker) brawl decks.
