Since you have received SA and AIP that means, the sponsor met all the eligibility requirements as well as the applicant. AIP proves that the applicant is ready to become a permanent resident and have met all the necessary requirements including relationship and cohabitation requirement. The final decision is usually withheld until the following requirements are met:
- Background
- Security
- Medicals
Police clearance is part of the background check and falls in the "Criminality Check" category. As soon as it's done, I believe a final decision will be made assuming medicals and security is completed.
If they needed more proof of relationship or cohabitation they would have asked before issuing AIP. At this point they won't ask you additional documents related to the aforementioned pointers, but they can ask you documents related to Background Check if needed.
I am on the same boat.
