Got it. I watched one video of a freewheel/cassette installation where the guy just screwed the entire assembly (gear set + freewheel) to the hub, basically hand-tight, and that was it. And I stand corrected that it is the axle nut, not the motor cable, that is problematic for the freewheel tool (though I don't know what "DNP" stands for).
This is all much clearer now. Thanks again for your help!
