Able to isolate an apparant wiring short on the Starter Relay side, somewhere between the Relay itself and the Starter. Ran a new 10-gauge wire from the Ignition Switch (White "hot" lead) over to the Battery Positive terminal. Doing so effectively completes the Starter circuit on this 1996 Prism. Anyway, that resulted in restored (electrical) connectivity and the vehicle now starts like a champ. I'm not entirely sure why this solved the problem other than to say, from the Wiring Diagram, I ended up replacing half that Starter circuit by running a new wire from the Ignition Switch over to the Battery (Positive) terminal. Used new connectors and carefully taped them, as well. Problem solved...finally(!). Happy New Year 2015!!