Thanks so much for the awesome suggestions!
@arnoldcp (1) I didn’t use any bungee cords on this test, I have the attached to the router, but I figured it was plunging fine on its own. (2) I’ve attached a photo of the anti-rotation groove, and I’m pretty sure you are correct, you can see where the tab is rubbing about halfway down and there’s a disjoint between the top and the bottom. I’ve started filing and I’ll test again once I’ve got things assembled this weekend. (3) Yes to the deflection.
@geeklimit I’ve tightened the housing grip, and I’ll test to see that the motor continues to move smoothly after I file down the anti-rotation channel.
Again, thanks for the suggestions! I’ll report back over the weekend.