Ok, maybe I slightly misunderstood. I thought you got it to work, but only in a single workbook.
Step by step:
- Custom style should work, as per my very first response. I made the text pink, and you can customize your style as per your liking. If that is still not working on your end, I do not know why. I guess a remote session might help to see if a step might have been missed or if you found an exception.
- "Just cant figure out why it isn't transferring to OneStream." --> It technically does not transfer to OneStream, but you can use it on a quick view in Excel. Make sure to create your style and then select it for your quick view. If you close your workbook, you need to create the style again unless you saved the style as per previous link (Microsoft help).
- "Does the custom style persist for all OS quickviews?" --> Yes, if you save it as per previous link and select it for each quick view.
- "I just noticed that the custom style doesn't appear on a new Excel file. I thought it would continue for all files associated with my OS add-in." --> This is what I was referring to in my previous post. As cell styles are an Excel functionality, they can only be re-used in a new file when they have been saved accordingly (Microsoft help link).