Wow. Your application is processed pretty fast! Congrats on the pre-arrival letter.
This is what I saw from another thread. Hope it can give a reference on the timeline:
File Recieved - April 16,2019
AOR- May 28, 2019
BIL - May 28, 2019
Biometric done - June 01,2019
Medical Request Letter - October 18,2019
ADR- October 22, 2019
Medical passed - October 31, 2019
PAL - November 09,2019
ADR- (Ht & eye color / passport page Principal Applicant)- November 11,2019
DM & PPR- November 14,2019
Passport Submitted - November 18,2019
VISA STAMP & COPR —APPROVED - November 26,2019.
So you might expect to get ADR (Additional document request). IRCC might also order a criminal/background check on you.
Nonetheless, you are almost there!