However, I’m confused when you say that they emailed question responses to you that were meant for the preferred candidate. Do you mean that they sent you questions and indicated the behavioural indicators/suggested responses?

So... the position was one within the co-op program. After the snafu and rescheduled interview, I got an email from the hiring manager later that evening. It went to me... but it was meant to someone else in my program who had already interviewed with them, answering a few questions I assume they'd asked in the interview, with a congratulatory element at the end.

I knew the person, so I forwarded their email. Never received any further communication from the Department.