DNG files are "RAW" files -they cannot be edited.
You can only export B&W versions as (pixel based files) such as JPG or TIFF
You can export copies of a DNG, but they are still RAW.
You can embed data in a DNG file (containing similar to the XML sidecar files with NEF and CR2 raw files) but the editing will only be visible in software that can interpret the raw data (such as Lightroom or ACR)
Got it - in fact now that I look at the exported DNG files they are all unedited as you say. This was very helpful, thank you! It also leaves me to learn something new on how to embed data in DNG file!
Yes, if you edit a DNG photo in Lightroom, then "Save Metadata to File" [CTRL+S], this will embed the develop edits into the DNG.
You can give this DNG file to others, and with Lightroom or Photoshop-ACR they will see the image as you saw it edited.
This is great - thank you very much!