I called this morning, and my application is ok, so nothing to worry. When I asked about the wrong accreditation number, the operator said that they just need to be sure that the immigration officer will check the cover letter first... When I asked if I have to do something about that, she said I have to do nothing. I suppose should be ok.
Regarding the prioritization, I partially agree with you. It's not unreasonable for an employer to set a deadline for a job offer, I cannot expect them to wait for me forever. In my case though, I think the deadline is a bit too short.. We will see
I sent a prioritization request to the email, because reading the topic you linked, I had the impression that it's worth to try... We will see! Thanks