Here is an update on my case.
The online instructions only asked me to submit the 'required' documents so that was just as follows.
1) Instructions printed from
https://ais.usvisa-info.com/en-ca/niv
2) DG160 confirmation page
3) Current and previous passport (that had my expired US visa in the same category b1/b2)
4) 1 2x2 photo taken in the last 6 months
5) Double-sided copy of Canadian PR card
Note: I did not submit any additional documents like proof of employment or bank statements as it was not mentioned that they needed that AND it said twice in the instructions to ONLY send the required documents.
25 Jan Dropped off application package + passport to Canada post
26 Jan Package delivered to US Consulate Toronto
28 Jan Online tracking status shows as application received (entered in the system for processing at US Consulate)
For mail-in cases: It means that the visa application has been received by the Embassy and is undergoing review.
1 Feb Status changed to Administrative processing. This status means: the visa-issuance process (visa has been approved but not yet printed)
3 Feb online status changed to Issued
I will update here as and when I get the passport back.
To track updates on your case after sending it via the dropbox option, please use
https://ceac.state.gov/ceacstattracker/status.aspx
You'll need your consulate information and your DS160 number.
For the meaning of status please refer to
https://jp.usembassy.gov/visas/nonimmigrant-visas/visa-status-check/