@doctormo Oh, yeah, the shape-builder should be very good for this! Exciting!

In Illustrator I'd do: Duplicate the object with Ctrl-C and Ctrl-F, change color, A for Direct Selection (Node View), C for Scissors, cut the object anywhere on the path V for object selection, delete unneeded part, P and for pen tool to draw the shadow. Workflow is quite similar but a few less steps, I think.