You see the animation *path* over the timeline clip with ctrl v.
You copy keyframes with alt shift c, paste is alt shift v (means overwriting from current playhead/skimmer position!).
Draw mask is a useful tool, but limited in many respects. Not suitable for complex compositions. For tracked subjects, use SliceX/TrackX (plugins). For animated graphics, use Motion, for advanced roto After Effects.
No worries. I also noticed when you keyframe the transform controls on the mask there is no option (that I can see) to change the movement from Ease in, Ease out, or linear. Which you can adjust when using the Transform controls for regular clip movement in the inspector...?