The first one is really out of the scope of what I can help with for this tool. You can potentially look into nearrect for positioning the new screen appropriately, or style your buttons instead of opening a new screen.
For your second question, you can use buttons that have the Scroll action, if I understood you. Generally if they're using the mouse though, it won't make sense to have buttons which set focus elsewhere. You might be better served having a variable keep track of what button is "selected" and style it based off of selectedness rather than hover state. Then you can execute the appropriate button action based on which button is selected.