Yes, these SVG files were used where was possible. Also this folder contains several SVG icons used in Environment and Editor settings dialogs. However, the icons for these dialogs were not created yet.
By the way, only icons really used in C::B is created. Some icons are in the source tree, however are not used. I remember this is the case with ThreadSearch plugin. It can be, that I just overlooked something. Let me know about it.
SVG files for icons were created as close as possible to the existing *.png icons. However there are exceptions:
1) misc_16x16.png icon. It is blue 3D gear used on "Logs & others" window in "Build log" and "Debugger" tabs. It is quite (too) complicated icon to make in SVG. This icon was changed with a simpler 2D gear icon found in the C::B repo. See screenshot.
2) trash.png icon used in "Start here" tab for reopen recently used projects (can be found in /src/resources/start_here/). I do not want to hurt anyone, however I dislike this icon here. It is like saying for the user: "Your work is just trash. If you like, take it from there." I changed it to an icon with rotating arrows. See screenshot.