I’ve delivered to “AV” companies for years… my two cents.
My suggestion is to let them tell you what they want. Ideally, this conversation should have happened before you started. Assuming they are experienced (and know what they are doing) they will know what they need. They’ll know what frame rate they will be running for playback, what resolution, what aspect ratio (yup, their idea of HD and yours might be different) and what bit rate their players can handle.
(This conversation will also give you a clue as to how competent they are)
Oh, and don’t forget about the squeaky part of the picture — audio.
It is tempting to urge them one way or another, but if something goes wrong, or looks off or hiccups, and you have suggested the specs of the deliverables then they can point fingers at you. Since you aren’t on site, you won’t know what happened.
They also might have specific needs like (x) frames of black before show start and (x) frames of black at show end or freeze on last frame for (x) frames.
I’ve had to deliver DCPs, ProRes 4444HQ, mpeg 2, MXF, AVI, WMV and a few more.
The most successful playback has been when the show company drives the conversation. If they know what they are doing. If they don’t, they can take a ProRes file and make it look like a 500kbps h.264@12fps.