I had an appointment but they didn't bother to check. I booked the last slot 4pm-5pm. All together 1 hour including 20 min observation time after vaccine.
I have extended my Non O Visa quite a few times with 400k in account for 2 months but I never transfered from overseas. As you mentioned you have enough money in your wife's account, so u can transfer from there just to save a day or two and at the same time you can transfer from overseas, just to be on the safe side if they really want to see money came from overseas.