How many people are you sponsoring? Do you have a cosigner? If you are sponsoring mom and dad =2. If you have a cosigner = 2. Total is 4. If no cosigner and only one parent =2. No children or dependent children of your parents.
Every year it changes. So nobody knows for 2020 what the requirements will be. So make sure you are meeting the present requirements. Your spouse can be a cosigner too.
Remember IRCC said if you cant get these documents you should write an explanation letter as to why but I think you have to make an effort first and probably send and communication you got from these countries while you were trying to get the pcc.
Yes, it is a part of your parents /grandparents / dependent (s) over 18 background checks and is needed except canada unless they ask for RCMP. We all get the same letter regardless of what of the immigration department we are dealing with.
You could apply for supervisa for her. Supervisa is not a regular visa you have to buy insurance and the visa is for 10 years and she can stay here 2 years at a time without extention.