First off, please know that your first year students are likely in a Learning Community course where they will likely do some sort of library tour or other activity where they talk about library resources in a general way. Each Learning Community has a faculty or staff instructor and a student Learning Community Leader. If you don't know who these are for your class, you would likely be able to find out by contacting the Learning Communities program in University College.
Secondly, in my experience, most students I've seen participating in scavenger hunts or the "Amazing Race" activity are concerned with completing the task as quickly as possible. From what I've observed, there doesn't seem to be much engagement with the actual sources of information that they've found.
Some suggestions for making scavenger hunt activities more focused on information engagement: