Rapid-fire answers:
- No hand tool. If you want to move around in the canvas, depress the space bar and click-drag.
- Tools>Selection tools>Intelligent scissors|Foreground Selector. You can also use a layer mask and paint it with black/white. If the object is text/logo, there are quicker methods.
- Windows>Dockable dialogs>Paths and toggle the path visibility (eye icon, like with layers)
- If you mean the fixed dotted line, this is the layer boundary. Toggle visibility with View>Show Layer boundary
- Drag from the Layers list of the source image and drop on the canvas of the target. If in Single Window Mode, you may have to hover over the target image tab to switch to that image.
- Dragging a file to the canvas of an open image adds it as a layer in that image. So if you want to open a new image, drag the file to the the Toolbox.
- If it"s fixed ants it's the layer boundary (see above). If it"s moving ants (selection), see View>Show selection