I reckon you are quite likely to get an offer. Like you said, once Auckland waitlist moves, there might people who reject their otago med for Auckland instead; freeing up more space.
However, I am quite confused as to why UoA still hasn't release any waitlist offers, historically, they should have released them by now. People have gotten different responses from Auckland, some have said that courses are at full capacity and no waitlist offers will be made until the courses free up, while others say no waitlist offers have been given since first round.