Hi,
AL means authorization letter from IRCC for travel purpose. My situation was almost same like you. My wife and daughter's VISA and medicals expired in September 2020. I raised a travel ready webform on September 30 mentioning all details like
Case of Family reunification
why they were not able to travel earlier
Quarantine arrangements for my wife and daughter (attached lease agreement)
My company letter to prove that I am employed and can take care of them
I received generic response for the 1st 3 webforms (same details in each webform). Finally got the ALs after 3 months (almost). For your reference please find below extract from the AL. Hope this helps.
You must carry a copy of this letter along with your passport as proof of your authorization to travel to Canada.
On March 18, 2020, the Government of Canada announced travel restrictions to Canada to reduce the spread of COVID-19 and protect the health and safety of Canadians. Your application for permanent residence (PR) was approved on 2019/11/01 and you were issued a confirmation of permanent residence (CoPR) document. If you are from a country that requires a visa to travel to Canada, you were also issued a PR visa counterfoil in your passport. As your application for permanent residence was approved on or before March 18, 2020, you are exempt from the travel restrictions. As your CoPR XXXXXXX and PR visa XXXXXXX expired on 2020/09/22, we have extended their validity until 2021/04/29. At this time, we are not printing and mailing new CoPRs or PR visa counterfoils.
For your travel to Canada, you will need to:
bring this letter, along with your original CoPR and PR visa
show it to the airline as proof that you are exempt from the travel restriction and that the validity of your expired CoPR and PR visa have in fact been extended.
use this letter before 2021/02/16