Sivir ricochet does not trigger death fire

It's not a bug. Ricochet is an auto attack buff and not an actual damaging ability, so it won't proc ability effects. Same principle applies to Jax/ Empower, Rengar/ Savagery, Darius/ Crippling Strike, etc.

Even if it did work, I would pick Fervor of Battle anyway. It stacks very easily on Sivir and makes the Ricochet bounces hit much harder.

Are you referring to the finisher animation? Because I'm pretty sure they were stopped at the end of All-Stars