I seem to have put too much detailed information in my previous question, confusing the masses. My apologies. Let me try again from a different angle.
I want to rotate labels interactively/visually, using edit tools. I don't want to use the Data defined Rotation method, found under Layer Properties > Placement.
Is there a way to interactively rotate labels in QGIS using any of the edit tools?
While Data defined Rotation works well, it is tedious to set the text rotations for a feature, having to manually enter and "guesstimate" the text angle value into the attribute fields. Especially for point and polygon features.