I would say applying for a US visa with a Canadian PR is the same as applying without one and the result would be similar to if you had applied without one.
Technically it shouldn’t make a difference. However, if you’ve already moved to Canada and they do ask you you about Canadian PR you cannot lie. If you’re a recent immigrant to a third country (Canada) some officer may consider you an immigration risk to the US (e.g. why are you applying for US visa - especially if a work visa - if you are a PR in Canada). Even though they are required to follow the guidelines they have discretionary powers - now more than ever - to reject your applicant for any reason, or no reason whatsoever. However this may be an exception rather than a norm. Lesson: Don’t brag about Canadian PR status in US interview unless they ask you (your passport probably has PR visa so they’ll know anyway).
On the other hand, another officer may consider you a low immigration risk to the US and approve your US visa since you now have ties to Canada and will return to maintain your PR.
Filing for a GC on a non-immigrant visa is a big red flag and is considered violation of your visa terms and therefore would affect future visa applications.
Technically, yes, however, you when you are getting the visa and entering US you shouldn’t have immgirant intent, but you can develop an immigrant intent later. Which is why lawyers are comfortable filing for EB-1/2/3 on, say, F-1 student visas. H-1 is a dual intent visa so that’s OK.
As a side note, technically, immigrant intent is only demonstrated after I-485 is submitted (change of status form). I-140 is not technically immigrant intent however officers can make a discretionary call and reject visas on this fact.
There are these small nuances about applying for US visas that make life tough for unsuspecting applicants.