This is very interesting idea. Thanks for sharing! My only doubt is with gear motor. The cheap ones don't last long at all and in my experience fail somewhere between 20-50 hours of continuous operation. The good ones last hundreds of hours, but cost hundreds of dollars. Maxon and Escap are still in business because of that. The weakest point is the brush wear. Second problem is the gearing, which is hit and miss and can fail unexpectedly. Planetary gears last much longer, but are several times more expensive.
On the other hand, you probably don't need the motor to last a thousand hours. At 40ms per advancement, it can empty a 15,000 component reel in 10 minutes. But the gears can fail sooner because of the jerky stop-n-go operation.
I would look into using some kind of a small steper motor to skip the gearing and allow for more precise tape advancement. In that case your only wear item would be the ball bearings in the motor, which usually last well into thousands of hours. Nema8 is 20mm square. Is it going to be a problem? What's the maximum width of the 8mm feeder are you shooting for?