The Guide says that teams with BYE should send for CB purposes. But, since there is only 1QR, there is no CB.
But, The Guide also says that teams may sign up as ALTs after Final Deadline. Now, which is the FINAL Final Deadline for that? The QD release? The OOP release? The Guide says nothing about it.
The time matches start.
And, if player X knows he has BYE and only 1QR and decides he has no reason to send picks, but with 10 minutes before sending picks deadline new player commits and sends what happens?
Nothing happens. Alternates don't replace byes, just players who forget to send picks. And players who have byes don't necessarily have to send.