Seems to me that when you define an event and specify the date or dates of that event, you'd want to pull up a list of all available employees. There are several ways to do that and much depends on the structure of your tables and relationships.
You don't need a "massive 45 cell" calendar to do a calendar in FileMaker. It can be as simple as this example: https://www.dropbox.com/s/e8d03xvwe8vtz85/Calendar.fp7
This is still in the older file format, so use Open in FileMaker's File menu to open this file and convert it to the newer file format if you are using FileMaker 12 or newer.
Thanks, this simple calendar is something i can easily work with, I've seen others and they were just .. not good.