I do not believe that speaking to someone in CBSA's Tier 2 department was in fact someone in a call centre. I do concur with the balance of your post.Please don't take offence.
But your expectations about what a call centre person can know, and in addition, what a government rep can or be willing to say, are 'misguided' in that you will not get the answer from them you seem to be attempting to extract. They will not say you 'will' be admitted.
As was noted in another post, they will almost always fall back on "you should have the recommended documents." They will almost always fall back on some version of your entry is not guaranteed, because the border agent decides.
Refer to the language "if they are satisfied" - which by construction means the 'we cannot say in advance whether the CBSA officer will be satisfied' response is always correct. And not coincidentally, reduces the likelihood they will have someone claiming the call centre person said they will be admitted - because they are trained to never, ever say that.
I was ultimately trying to find out from CBSA whether or not Phase 4 and 5 of the Beyond the Border initiative have in fact been implemented, regarding U.S. citizens. Seems plausible that if they have an answer that should share it, since the initiative has not been kept secrect from the public at large. I do believe that my passport and PRC are linked together in the system(s) that CBSA uses to monitor movement and understand that the only entry records into Canada, since becoming a PR, would be shown on my PRC history, whereas exit data would be information from my passport being scanned when leaving Canada. If Phase 4 and 5 have been in place as planned (Feb 2019 and June 2020, respectively) THAT would be a big relief for me/us.