If you have a heavy caster comp in a 24-man raid giving Ewers to a BRD who actually sings Foes is probably a larger DPS increase than trying to fight for Expanded Balances for your party. The nice thing about Ewer into BRD Foes is the fact that its effective as just a single card versus trying to potentially fight for Expanded Balance for optimal Balance usage in your group.

I would burn a Time Dilation for Ewer, but not necessarily a Celestial Opposition unless I have other buffs going as well that can go with it.

Also yes, if you're going to buff an Ewer in this capacity please make it Extended and not Expand or Enhance ^^;....