Hmm, neat little feature. I get an inkscap(e)y feeling from this but I don’t know if I would use it on my tablet 
I would more likely use the distraction free mode on a small screen sized tablet and the popup-palette.
Although I have to go out of this mode if I wanted to switch tools as the popup-palette only shows when using a brush, but that is another feature request.
I think I would use it, if I had an extra toolbar available, which I then could place next to the dockers. I have not found way to add my own toolbar btw. Is there a way?
I would activate the docker, make my changes and start to draw and would expect, that the docker hides when I tab to draw or change to another docker. That is how it is generally done in other software for tablets
For the Icons… I don’t know if we could incorporate Lucide Icons, which is also an open source project
Or there is someone of our community who creates some, we would need a design preference for the icons to look coherent when many people contribute. I would also help with contributing icons to krita.