Don’t have an answer… Interesting icons, but I would not set black & white icons as default icons. I think LibreOffice should have the icons specific to the operating system it is run on. This is in my humble opinion the only “professional” criteria. This would eliminate user’s confusion what are the actions taken when clicked on icons.
There should in my humble opinion be other operating system specifics integrated into LibreOffice like File | Exit (Windows OK) on Linux distributions should be File | Quit. Tools | Options should be moved to Edit | Preferences. Firefox does nice job of this kind of adoption to make it more natural to the native users of operating system.