Lot of information on this thread but scattered, so just for confirming, if anyone with experience could please ratify.
1. OCI and SC can be done together (but only in Vancouver jurisdiction?)
2. While SC can be applied without appointment, Visa and OCI need appointments.
3. If you chose postal, then also you don't need appointment, and can send SC and OCI together.
Given the long wait times (2 months from today) for appointment, it appears Postal method should be the fastest (especially if done carefully avoiding back and forth due to mistakes).