Nothing specific to add regarding your invitation from the committee, however, I read some interesting advice recently that I feel is applicable here.
If Osgoode has taken the time to invite you for an interview, they're hoping you're a candidate that will pan out for them. In my view, there's no reason to be concerned as long as you answer their questions candidly. I would wish you luck, but I sincerely believe you won't need it!
As someone who is also anxiously awaiting admissions I would say that some comforting things that have helped me with managing if I don't get in this year are that the average admissions age is 25-26 years. I obviously don't know your age, but for me this gave comfort as it meant if I do get rejected then I will take the time to invest it in relevant work experience and boosting my LSAT score without "falling behind" the general population in law school. While age doesn't really matter, it helped me rationalize that I am really young in comparison to other applicants and I should not take it as an insult/discouragement to spend the same amount of time they have taken to invest in getting into law school. Also, you can always transfer after 1L so if you dislike your school then you can always transfer!
If you’re hired, I would confirm with your firm before committing to anything.
I don’t think it’s safe to say anything at this point and, depending on the firm, you may not even be allowed to physically enter the office absent exceptional circumstances.