Absolutely no costumes. [They're having a civilian wedding. As small a one as possible. That way it'll be way less of a target for possible supervillain attacks and other cape fuckery. He would like their tiny daughter to be able to attend safely, after all.] And we'll keep it as small and stress-free as possible.

[Barry smiles wryly at the threat of divorce.] No Bruce. I was just thinking Clark and Diana from the League, actually. [Both are decent friends, and not at all likely to start drama or arguments at a wedding.]

Guy is going to be rowdy enough without inviting anybody else that you're going to spend the whole wedding arguing with.