This method of attaching a disc assumes that you are not directly mounting the disc to the motor, which I assume Jack, you will be doing as its a kilobot cos you'll just want to screw it to the brushless motor.
The way you said with the LED, drilling holes in a circle around the top so its visible when spinning has been used in antweights before, you'll have seen MBY, this seems to work fine. As for the link, I think you can make it accessible via the base, like Dizzy Tilly does. As it's only a kilo robot, and it'll have failsafes in it anyway, I don't see why you wouldn't be allowed to do this if a featherweight is.