Leaving an update in case anyone else happens to be in my situation: Though I did fill out the DS 5535, it never came up again. I was approved on the spot at the interview, and the visa is issued and in my hands. It feels very surreal. I don't know if the link was sent to me in error, or they determined it was unnecessary, but it is possible to receive a request to fill out the ds5535 in an email in advance of your interview and then not enter AP. I have had a Nexus card my entire adult life, which means I've already had a background check and biometrics done-- I don't know if that affected anything. I wish I knew the why behind any of it so I could share Wishing everyone luck in this really difficult process.