Ryan,
Look at notification::new tcl proc https://openacs.org/api-doc/proc-view?proc=notification%3a%3anew
which has the concept of "dynamic"notifications. So you could create a notification on a calendar item, that is sent to just the person who requested the reminder.
Along with that, my experiement for scheduling notifications for a certain time and date was successul and I will be adding this to CVS later today. I can tag/release notificaitons for 5.2 for this after some more testing.
