Sure: I'll take a shot at a "feedback surveys" straw man for you, and then you can pick it apart to refine and improve what you need.
So! Not really knowing your requirements (but admitting that rarely stops me from solutioning) I suggest you:
Add a Task called "Feedback Surveys" to your Templates at the end of the Project, with an Approval Path on it that means "Surveys completed, reviewed and filed" as you see fit
When that Task is reached on a Project, create a "Feedback Survey" Issue for each respondent from whom you seek feedback, and assign it to them for completion. This Issue approach allows for 1:many responses (vs Task or Project Level), consolidates them "under" the Task (canna close with open Issues, by design, which is A Good Thing), and allows (worst/best case) a "serious" Issue to be escalatedinto a Task or Project with a life and timeline of its own. Even if you don't need it for a long time, it's an elegant path, should you need it someday.
Getting back to the Now...each respondent will then complete their survey in due course (BONUS: if you seek Feedback Surveys from folks who do not normally log in to Workfront, you might be interested in our OCD With Mail To solution; ping me for details)
In time, when they're all complete (or at some cutoff, when you complete them for them in a "no response" Issue Status which equates to "Dead"), all Survey Issues will be complete under that Feedback Survey Task
At that point, you review them, file them, and -- at long last -- mark the Feedback Survey Task as complete via the Approval Path, and the Project itself as Closed.