Question: Can only PDGA Approved glow discs be used for sanctioned play in the dusk and dark?
Answer: The PDGA office has approved a blanket waiver so any PDGA Approved disc may be used with glow stick or LED light attached, preferably to the underside of transparent discs, after sunset in your time zone. In addition, LED lights taped to PDGA Approved discs can be used during daylight specifically when there is sufficient snow cover on the course and the LED might make the disc easier to locate.
Non-PDGA Approved discs such as those with built-in LED lights cannot be used at any time during sanctioned play.
I don't think ribbons are legal, but LED's are legal if it gets dark, or if there is enough snow cover to help locate them.