Thats a good question...
You see, the path biometrics take is somewhat of a twisted on. Atleast for inland folks.
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/mandate/corporate-initiatives/biometrics/process-steps-2018.html
It goes like this You->Service Canada->RCMP->IRCC->CBSA . Unless something has changed recently.
Also, Among other things, BG checks include Criminality, Org. Crime, Security. Security is dealt by CSIS. Criminality and Org. Crime by RCMP.
I am not 100% sure, but security usually start the last, except for PNP people. So, Criminality and Org. Crime are done before that. That means RCMP does processing before that. Now I am guessing, RCMP will need your fingerprints before it can do criminality checks. I mean, other than that, It could verify your PCC but thats the extent of it.
So, yes, biometrics blocks Criminality (AFAIK) and that in turn blocks Security.
So your BG Check (criminality and security) *should* in theory be done after biometrics.