From v9.5.2, if an event from the Apple Calendar app is dragged or pasted into a Tinderbox view has invitees, the names of the invited people are listed in a system attribute, $Participants.
Whether individual participants are retrieved as the person's name or as their email address relates to the data passed by Calendar and is not due to actions by Tinderbox.
From v9.6.0, imported calendar events are assigned the prototype Event if the prototype exists, but only if the newly-created note wasn't already assigned a prototype by the OnAdd action.