I'm wondering the exact same thing! I thought I would have more time to submit my applications, but now I'm worried that I need to finish everything sooner so that my references can get sent in on time.
Edit: I reread the "Referee" section in the OLSAS application and the way it's phrased, I think that the referees can essentially start filling out the form as soon as we select "send email" and I assume that it'll all be saved within our application/tied to our application number since the reference section is launched from the application itself (if that makes sense). I might reach out to OLSAS to confirm, so if I do I will update you. Here's a copy/paste of what I read:
Once you add a referee, select "Send Email" to notify them about completing their online reference form in a secure environment. If the referee does not have an email address, download the form and forward it to them. They must mail it to OLSAS when complete.
Checking the Status of Your References
You can check the status of your references under the "Actions/Status" tab:
Email Sent: Your email has been sent to your selected referee.
Form Viewed: Your referee has viewed the reference form.
In Progress: Your referee started to complete their reference, but has not submitted it.
Received: The OUAC has received the reference from your referee.