bad IV Fallen Celica

i'm not really in a shortage of red units so i can stand to get rid of her until the next time she comes up in a banner.

She is +HP/-Spd (just like my only Charlotte, RIP) so i'm gonna give Chill Spd to someone else.

I have a few candidates to choose from but the decision is still unclear.
1. healer/dancer to better support my team
2. someone who doesn't need the speed and has an open B slot (probably someone slow like Cherche or LA Roy considering all the fast units need desperation) to support the team.
3. a Firesweep user (my firesweep units right now are Cordelia[both versions], Soleil, and Roderick. B.Cordie has cancel affinity, Soleil has wrath, and roderick and regular cordelia are mostly built but unpromoted)
4. Debuff dagger unit (pretty hard to pick bc all my dagger units have full B slots that are either wind or watersweep)
5. Some rando speed nuke with Aether