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?