Felicity Smoak is a character created specifically for the TV series and doesn't have a presence in the comics. The show introduced her as a unique element to the story.
Mia Smoak is a character created specifically for the related show or other media and doesn't have a presence in the comics. The comic storyline didn't incorporate this character.
Well, the status of Felicity Smoak's life or death in comics isn't straightforward. Sometimes she's alive, and in certain story arcs, she might be shown as dead. It all comes down to the creative decisions of the comic writers and the direction of the particular story.
I really like the fanfiction where Felicity is pregnant and it delves into her relationship with Oliver during this time. It shows how their love grows stronger as they anticipate the arrival of their baby. It's a heartwarming read that captures the essence of their characters well.
In the comics, Felicity Smoak's death could be quite complex. Maybe it was due to a major villain's attack or some unexpected plot twist. But without detailed reading, it's hard to say for sure.
Another option could be a new character introduced specifically for the fanfic. He could be a brilliant scientist like Felicity, and they meet at a tech conference. Their relationship develops quickly, and he is the father. This would open up new storylines about how they get to know each other better during the pregnancy.