Too bad about the Spooky Tooth wheel, I almost bought one once, glad now I didn't. It should be a piece of cake (with frosting even) to design and build a wheel with a rear sprocket that will not come off. Since it came from China, I guess that explains it. They can't seem to get anything right.
I would definitely NOT use that band brake, nor would I connect the front and rear brakes together. Doing so is just asking for a crash. Honda has built several motorcycles with linked brakes, including my former '95 Goldwing. These things are dangerous. When you apply the brake hard, the weight transfer takes almost all the weight off the rear wheel, making it super easy to lock up and put you down. When I have to make a panic stop on a motorcycle, I do not even use the rear brake. If the front brake is held on the verge of lockup as it should be, there will be no weight on the rear wheel, and just touching the rear brake will lock it up. The rear brake has it's purpose, during normal riding, several maneuvers cannot be done properly without it. But don't touch it in an emergency. Bicycles seem to be a little more forgiving, probably because of their much slower speed. Still, if you lock up the front wheel, the rear wheel is going to come off the road. Not that I'm recommending locking up the front wheel, and enjoying the almost immediate crash that would follow, but if you are hard on the front brake, it's better not to touch the rear one.