First strategy I really dislike... That Polymorph Attack can take Ikky down und since Chrom and the Flayer are pretty low after their fights AND cannot attack first - this situation WILL lead to losing the fight. This strategy is really not recommandable..
The team is a good, but the arcane explosion is unnecessary, I also rewrote the script to make it look more clean:
ability(Surge of Power:593)
ability(Flock:581) [enemy.aura(Black Claw:918).exists]