Application date was June 2nd. I did submit a webform in late June but that was for sending them my new IELTS result; apart from that I haven't submitted any web forms.
Wait until the refund/deferral deadline at least. Find out how much refund your university offers if your study permit gets rejected (mine refunds 100% of tuition fee). If it is 90-100%, I don't see the point in deferring.
Your time spent studying online while awaiting an AIP will count for the PGWP requirements as long as you applied for a study permit on or before September 15.