Unfortunately, there are no step by step process. Your medicals can be asked in the beginning while for others, the BGC starts straight away. It depends on the VO and the officer assessing your application. Also, if there are any red flags, it may take longer. If you reside in Québec and inland, chances are they will delay your file and start processing it almost a year after it was received, regardless of then the CSQ is received.
When it comes to BGC, they have to verify that you're not inad under s. 34, 35 and 37 (security) and 36 (criminality). This is done by other agencies and not by IRCC. I think they send an ATI request and background check request to RCMP and CSIS. Once they get the information back, they will upload GCMS which is why you get a ghost update. When this is done, an officer needs to verify your eligibility by completing the inad assessment (non-compliance, misrepresentation). They will also check that you passed your medicals but this is done separately when you send them the test results. The same process is done for all dependents.
There is no LICO for spouses. So once all this is done, an officer will start reviewing your eligibility. That's when you see in GCKey that it changes to we start reviewing your eligibility. Usually, if your case is straightforward and there are no red flags, as they review the entire application, if everything is fine, you'll get SA and AIP. Then, normally you need to attend an interview where an officer will ask you a few questions to confirm the relationship is genuine and that is considered your landing instead of flagpolling. That's when you get COPR. These days, the interview is either a phone call, email or nothing at all.
Note: an officer often reviews your application and makes recommendations, then a lead officer is the one who approves or denies. IRCC would preferably take their time to review the whole application thoroughly than making a mistake that will result in an appeal to IAD and another review of the application is approved. I'm not saying that they intentionally delay (except for Québec if we consider applications sent the same day to the same VO) but that they thoroughly check the entire application. If they don't, you can find out in your notes and you would have grounds to appeal for procedural fairness.
I don't work for IRCC but that seems to be what the process looks like... we a lot of waiting in between. Hope this helps.
PS If someone knows more or work for IRCC, feel free to share your knowledge. I'm still at the early stages (bgc haven't started) so I may have missed something.
