Hi MsRuby, ECAS will be unavailable for login until a couple days after you get your AOR or even SA. For me, for example, I couldn't log in until a week after I got my sponsorship approval.
The UCI number you got belongs to the sponsor. If you use that number, you have to enter in the Sponsor's information.
The Application/File number you use with the applicants information
Both give you the same information, pretty much. If the sponsor logs in, they'll see two boxes: one for the primary approval of the sponsor, and one for the PR application for the applicant.
If the applicant logs in, they'll only see their half of the PR application, not the half about sponsorship approval.
Also - ECAS is generally very delayed. It normally is not updated very often. For example, my ECAS says 'decision made' under sponsorship approval and that I'll be receiving a letter in the mail, although I received my approval a month ago
So don't worry that much about it!
