I think the way Copenhagen is written that it may lend itself very well to this intriguing idea of a Rhetorical essay with a Greek Chorus. There is ironical drama from the outset,
Bohr So quick and eager.
Margarethe Too quick. Too eager.
Bohr Those bright watchful eyes.
Margrethe Too bright. Too watchful.
Bohr Well, he was a very great physicist.
and it is drama that the Greek Chorus presented so well. You might model your chorus after Marlowe's Chorus in Doctor Faustus. He incorporates the Greek Chorus to great effect at the opening and the closing of the play and at various parts throughout:
CHORUS. Cut is the branch that might have grown full straight,
And burned is Apollo's laurel-bough,
That sometime grew within this learned man.
Faustus is gone: regard his hellish fall,
Whose fiendful fortune may exhort the wise,
Only to wonder at unlawful things,
Whose deepness doth entice such forward wits
To practice more than heavenly power permits.
You might begin with something like a Greek Chorus giving a brief introduction to the play Copenhagen, then end with the Greek Chorus providing your Conclusion. In between, you might insert a Chorus where ever it seems to suit. Interesting idea!
The Greek Chorus provided an excellent opportunity to summarize and introduce the action. It also was a way of commenting on it. The playwright could then direct the audience's attention to specific events or prepare them for important upcoming events.