For the colour picker - are you using the controller version? I put out an update with color_picker_controller.rpy which you'll need to use if you'd like the bars and color picker navigation to be able to be navigated via controller.
For your screen - I think you'll want something like the event_listener screen in the controller pack, which sits on top of everything. It's added to config.always_shown_screens. If you want this mouse to work everywhere, I believe you will need to grab the mouse events and then send out a modified mouse event, otherwise you are not going to be able to do things like click and drag bars, drag and drop, or viewports. I get around this with the virtual cursor by making it a container you can put the screen stuff inside, because most games won't have a virtual cursor to navigate their entire game, and then I can pass along fake mouse events to the container's children. You're probably going to need to pass along adjusted mouse events to the entire game. I'm afraid this is about the extent to which I can assist you in this matter, however, as your question is no longer related to my tools.