Let’s roll through the remainder of the Mass. OCM doesn’t give a lot of instruction on this part, but keep in mind that everything written about the music at entrance (OCM 1) applies to singing during the Communion Procession (OCM 17)
13. After the Offertory antiphon, verses can be sung according to tradition, though they can be omitted also at any time, even in the antiphon Domine Jesu Christe, in the Mass for the Dead. After each individual verse, part of the antiphon is repeated, starting at the place indicated.
More Roman pragmatism here. The music fills the time alotted for the ritual action. Music itself should not prolong the preparation of the altar and gifts.
14. After the Preface has been completed, all sing the Sanctus; after the consecration is made, all sing the anamnesis acclamation.
The rubrics also state the assembly is to sing these pieces.
15. When the doxology of the eucharisitic Prayer has been completed, all respond: Amen. Then the priest, alone, offers the invitation to the Lord’s Prayer, which all sing with him. He alone supplies the embolism, which all conclude with the doxology.
16. When the breaking of the Bread and the commingling are being carried out, the invocation Agnus Dei is sung by the cantors, with all responding. This invocation can be repeated as many times as necessary to accompany the breaking of the Bread, keeping the musical form in view. The last time, the invocation is concluded with the words Dona nobis pacem.
17. When the priest receives the Body of the Lord, the Communion antiphon is begun. The chant is carried out in the same manner as the Introit chant, and in such a way the cantors also may receive the sacrament.
See this post for our previous discussion on the entrance chant.
18. After the blessing by the priest, the deacon presents the admonition: Ite, missa est, and all give the acclamation Deo gratias.
Comments?
As always, I note the kind contribution of Richard Chonak who translated the Latin original of the second edition (1988).
Catholic Sensibility 
“Music itself should not prolong the preparation of the altar and gifts.” I couldn’t agree more. Music is the handmaiden of the Liturgy, not the other way around. Far too often I see the priest waiting and waiting after the preparation of the altar for the choir to finish. That really is an abuse.
In regards to section 16, I would have to find it but I believe that this has been superseded. I believe the current norms state that the form of the Agnus Dei is fixed.
The current norms on the preparation of the wine earlier in the Mass abrogate any need for extending the Agnus Dei litany on a regular basis. But I observe that a fixed form changes the nature of the piece from a litany to an acclamation with a special concluding ending. Thanks redactor007 for all your comments.