Workflow?

Firstly DNG files are NOT RAW files. RAW files contain sensor data and a DNG can be created from a converted RAW file, TIF, etc. DNGs have a small advantage because they can contain a profile, think of a profile as a LUT.

Topaz workflow, for which i would use a TIF image file, is listed here and it is recommended that DeNoise comes the step before Sharpen:

In point of fact DNG is a RAW format. That it is a generic format created by Adobe rather than a camera-specific manufacturer format is immaterial. DNG can, and does, contain all the same data as a manufacturer-specific RAW file. And while, yes, DNG files can be created from a manufacturer RAW file, they can also be created in camera and there are manufacturers that use the DNG spec for their in-camera RAW files. I know, as well, what a profiles and LUTs are.

All that said, whether DNG is, or is not, a RAW file format was not what I was asking.

WRT to the link to the document you provided, what Topaz may recommend is only one approach to using their tools. I was looking for how others use them in their workflows. Is that not a legitimate question to ask? Is it not permissible to ask about the issue of a RAW file being processed twice in two different TL applications? Or whether the pink overlay is something else others have experienced?

It is, to me, antithetical to a proper workflow to use noise reduction on a fixed file format like TIFF. I want to keep images in a RAW format as long as possible before converting to a pixel-based image file. Thus, applying DeNoise to a RAW file and saving the result as a DNG does that. I wanted to find out if others were doing the same. Is that acceptable?

Is there any way to edit Sharpen AI settings after rendering the image when using it as a Lightroom plugin? I often take time to create a mask in Sharpen AI, apply changes, then when I see the final rendered image in Lightroom, I notice something I want to change, and I have to start over with creating my mask and Sharpen AI settings.

Masking in Denoise and Sharpen is a new-ish feature and unfortunately you can’t save the masks at present. Even more annoying is that a mask saved by Mask AI can be used in LR, PS and other programes but can’t be imported into DeNoise or Sharpen, which are made by the same company.
I have been urging the developers to deal with this in the next upgrades. DeNoise has just been upgraded, and Mask AI not too long ago. So hopefully we might see an improvement in the next version of Sharpen. Don’t hold your breath though.