Question about spousal sponsorship.
I will try my best to fill out all the required forms in the highest quality. However in the rare event that I missed an unimportant form/document, will IRCC reject my application, or will IRCC send me a message (on "Permanent residence online application portal account") to request me to submit the missing form/document?
It depends. The documents you submit go through a three person review process. The first is the analyst review for file completeness. If the file is not complete, the analyst typically returns it to you. If it passes the analyst and the application starts to be worked on by an officer, they typically send a ADR (additional document request), or if it is an important document, or if the officer wishes, they can also return your file as incomplete. Once the officer has completed working on the case, then another officer reviews the completed application package to ensure something is not missed. That officer can pass your application, do an ADR, or return your file as incomplete. To many, a late stage return is heartbreaking for the PA, Sponsor and family.
The key is to double and triple check to make sure all required documents are complete and included as mentioned in the checklist and the detailed instructions site. Also ensure that all documents that require signature, notarizing, and translations are done as required. If in doubt about a detail, you can always ask here.
Best of luck to you and your family.