Manage Guest Account via Profile Manager
This is not possible.  Apple's Profile Manager is lacking in many areas, and this is one of them.  Apple does not provide any tools or documentation for managing the guest account on multiple remote computers, or creating a profile to define and/or configure them.
Update: It has been about half a year since I posted this answer and in that time I have gained more insights into managing macs in a school environment.  Here are my thoughts:

If you are managing student-facing macs in a school, your number one strategy should be to migrate to chromebooks. Cheaper, more secure, and a thousand times easier to manage.

If manage macs, you need to use something like Jamf to manage them.  Apple Profile Manager is lacking.

Even with a mac management service like Jamf, using the Guest user account for students is a challenge.  You will need to create your own &quot;pseudo&quot; guest user, and just manage it with scripts so it is always clean for the next student.