raw+jpeg with separate picture styles

We have to blame Canon for introducing such confusion into the issue of Raw, Jpeg and Styles. No question: The intended Style is only transferred with Raw IF the file is opened in DPP. There's the rub. Many posts never reveal which RAW processor is being used. The other issue of course, is that anyone can change their setting of any style IN CAMERA. When we discuss these issues, we hardly ever check to see if the parameters of a style have been changed IN CAMERA. In other words, each style name could be meaningless as users change the parameters. (Neutral, Faithfull, don't these terms mean the same? Surely something processed neutraly means that it isn't affected by the process, Faithfull! doesn't that mean "as was"? Personally, I have no need for styles but just in case I might open a file in DPP as against my preferred RAW editor which is Adobe Camera Raw, I have set the parameters on every style in camera to 0,0,0,0.

No, there is a small technical difference between Neutral and Faithful. To be really accurate a profile must be made for a specific light source and then applied in conversion to a photo shot under the same light. However, the usual practice is to make three or four profiles with different lighting and average them, thus obtaining one that is more or less good for a range of light sources. Neutral is this type. Faithful, however, is claimed to be colormetrically accurate for a specific temperature, 5200 degrees.

Even though you say you have no need of Picture Styles, I suggest you try the DNG Camera Profiles (same think as Picture Styles) in ACR. You might like them.