Actually, I called MU office, they would have been able to change the passport number typo, but when they saw
my passport copy they pointed out that the middle name was missing on my reservation, and refused to make the
change ( I always make my flight reservations with just last name/first name).
Anyway. after that last refusal, I bit the cost and cancelled and re-booked. It cost me about $100 CAD due to cancellation fee
and currency changes, but worth it for knowing there will be no unnecessary check-in impediments.
The only funny thing was that I was able to select the same seat that I originally had for the first flight, but
I was not allowed to select a seat for the second flight - although I had done so on the first reservation.