Who should I give Steady Breath to?

Back on the Legendary Tiki banner, I managed to get an extra Brave Ike that was better than my current one, so I turned the first into a combat manual. I do have a spare OG Ike to fodder for Aether as well. I have two candidates for Steady Breath and Aether: Nephenee (+Spd, -Res) with her special refine and Adult Tiki (+Atk, -Spd) with Res-refined Lightning Breath. I might merge Adult Tiki at some point, but not at the moment.