What would be her motivation for adventuring?
I can imagine any scenario ...
The most cliché would be meeting her later ... surounded by slaughtered Tieflings, hiding behind some crates or something ... with attackers looting/eating (depending on creature) corpses ... after the fight, you start conversation with her, and once she stop sobing, she will swear on her dead friends memory that she will never ever again loose anyone else, that she will become stronger and learn how to defend not just herself, but anyone who cant defend themselves, that she will make sure that nobody ever again will have to suffer losses as she just did.
Voila!
Adventurer created.
Apologies if I sound harsh here, but that would feel incredibly forced, story and mechanics wise.
Nothing in Alfira's current character indicates that her response to further trauma and grief would be to pick up a sword and declare bloody vengeance - in fact, that goes against her established character and destroys her character arc. Watching a loved ones die HAS already happened to her - and the beauty her entire scene/character is that with Tav's help, she chooses to persevere and create art. To live her life, and continue chasing her "itch to perfect a song" despite the horrors of the world. Remember, this is what the Weeping Dawn is about - not only is it a gift / memorial of her deceased teacher, but also overcoming the trauma of seeing her teacher die. "Smile and the pain will fade away"
It's okay to like an NPC and want to see more of them, but to traumatize Alfira into basically an unrecognizable version of herself so there's a story reason to make her a killer like the main party? Is that really the way to go?
Mechanically, it is also narrative breaking. Even if we assume a total civilian will completely uproot her life for revenge, and decide her life mission is to go on a crusade, how exactly does that make her fitting as our companion and adventurer? Is someone who's never held a weapon magically going to level-up to the party's level, and become just as powerful as the party because now she's motivated?
Remember, even in world-lore, a level 1 adventurer is VERY different from a level 1 commoner. Honestly, if this happened, it'd make much more sense for her to just be a quest giver for a "vengeance mission" and we can even make training Alfira into a fun side-quest.
If Larian wants to add a Bard companion, I have faith they'll be able to write one and add one in that works and fits way better as a companion, with an appropriately interesting back story. To force-fit in Alfira as a companion is doing Larian's writing abilities a pretty big disservice. Just because an NPC can sing doesn't mean you should make them into your bard companion. Just like you don't date EVERY single person you find attractive.
