ACES 2065-1 plus DWAB compression out of Nuke?

That is not my experience (see my post which you quoted). The write node still uses the colourspace chosen in the drop-down, and simply sets metadata to say it is ACES 2065-1 and has ACES primaries, even if it doesn’t.

You should not really do that if you are writing compressed data to the EXR, as the ACES EXR spec (currently) mandates no compression. So you would be flagging the EXR as ACES compliant when strictly it is not. Whether that would actually cause a problem for most software is a different issue.

You can indeed do that (you can copy the values from the metadata of an EXR written as ACES compliant) and it would be the more correct thing to do. Remember still to set the colorspace of the write node to ACES - ACES2065-1.

You should (of course) still test your pipeline, and ensure that any software intended to read the resulting EXRs interprets them correctly, and that notes are provided for those receiving them to ensure they can manually set the interpretation. The intent of the ACES Image Container flag is that it is possible for software to configure automatically, but this is certainly not guaranteed to happen. Try reading an ACES compliant EXR written by Nuke back into Nuke. It will not be automatically set as ACES - ACES2065-1. And setting chromaticities metadata is rarely anything more than a note for those who bother to look!