"First of all, make sure your profiles are in ~/.local/share/color/icc folder."
Yes, I'm curious about that myself. I think that's a file path or directory for Linux. Usually I can figure out the Windows path, but this time I can't sort it out. It's possible that's a directory of Inkscape's from version 0.48, and we just need someone to tell us where that directory is located now.
Searching my computer, I've found ICC profiles in inkscape/Lib/site-packages/sk1libs/pycms/profiles (that's for version 0.91) and also in inkscape/python/Lib/site-packages/uniconverter/share/icc (that's for 0.48), as well as MS Office directory, Dell, and printer drivers dirs. The search didn't find any ICC profiles for the current version of Inkscape. Also, the current version doesn't seem to have a python directory, at least not at the top level like in those older versions. It must be buried deeper (in the file structure) now.
I chose one but can't select it from the CMS tab list.
Why not? It's not there? Do you have something with a fill color selected at the time you try to choose it?
The short is that Scribus won't import any of my SVG files correctly as they "contain unsupported features."
It might be the flowed text. Try converting the text either to regular text, or to paths. Converting to paths would probably be better. The reason the text was missing is because of the flowed text. It only works in Inkscape. I don't know if fixing the text would fix the "unsupported feature error" but it might. But it will definitely make the text show up.
It might the unicode symbol in the title. Inkscape has had trouble with files that have odd symbols in the title, in the past. It's possible Scribus has a problem with it too.
It might be the filter on the background image. Can you create the same effect without using a filter? Try removing the filter, and instead reduce the Opacity.
I don't think the locked layers would be a problem, but if none of the above solves it, I would try unlocking the layers. Ooorr....somewhere in the back of my mind I seem to recall something about layers and Scribus. I don't have a copy of Scribus to check if it supports layers. Although note that that vague memory is from probably 10 years ago, and I'm sure Scribus has changed a lot since then.