1. Make it so the readout on the various tools can be located elsewhere on the screen. Often, the 'body of the tool obscures what is being measured.

3. For the Compass, it would be great if the circle (or other shapes) had sticky points along the arc that could be moved to points on what is being measured. Like what is done for measurement systems like MicroVu. A minimum of three points would be required. Options for more would be nice.
You'd just pick, drag, and drop each point in turn and place it on the arc being measured. The circle that's part of the Compass would automatically follow.