Hey, did you try linking it with his passport information? We tried to link it numerous times and then when we tried to do it with the passport info option, it worked. My suggestion would be to fill out the information that you wrote in form IMM5710 *exactly* and input his family name and DoB (dont do anything with app numbers and again, follow the spelling exactly as it is in 5710). I can send you screenshots if needed.
Perhaps it has been approved - mine was approved and mailed but with no e-mail. I figured they would of sent back your OWP by now (when they were doing the AoR) so I'm gonna be positive and say it is in the system.
I wish you luck ... try calling the CIC and asking for the OWP application number (select options 3-2-0).
Update: I have finally linked our OWP on GCKey! I'd tried using the PA's UCI and Family Name + Passport info over and over with no luck. Then just now, I managed to link it using Family Name, Given Name and Date of Birth - the key piece being that I entered:
Family name: Smith
Given name: John Middle
I know I've tried entering his first and middle name before and it didn't work, but for some reason this time, it did! It hasn't been approved though. The application says "Eligibility review hasn't started yet" and no email to be seen! The received date is 7 days before it would've been received- like I've seen others post here. So at least we're in the system!
I swear my agent dropped our OWP application on the floor and JUST found it this afternoon.
Application sent: February 4, 2019
Received: February 6, 2019
AOR: March 26, 2019
PR linked: March 26, 2019
OWP linked: April 10, 2019
OWP approved: Waiting
OWP received in mail: Waiting