Hi,
you can use this snippet for problem 1:
stage.addEventListener(Event.RESIZE, evtResizeWindow);
private function evtResizeWindow(e:Event):Void
{
WINDOW.setSizeWH(Lib.current.stage.stageWidth, Lib.current.stage.stageHeight);
}
For the second, you can look at the "setBackground()" or "alpha (to alpha the entire component),
is not hard if you search the api documentation.
Hope it helps.