It is not just about having a Quebec based job offer , the issue still seems to be that it is a well known fact that cannot upfront propose to live in or complete an initial PR landing in Quebec unless having applied specifcally through a Quebec immigration program. So whilst FSW/PNP and so on could initially land in Quebec as a connection with onward travel proposing upfront that is the intention to live/work before completing initial landing still appears to be a risk.This is just my opinion but they shouldn't deny the application just because you have job offer from Quebec. Applicants under EE FSW category can work anywhere and not bound to specific province like PNP. As per the email they want to confirm that you have well thought out plan to settle in Canada before granting extension. Job offer is the part of that plan. That satisfies their requirement point 1.
If you are really in doubt you can raise a webform and directly ask IRCC or create a post here with email from IRCC and your queries and tag legalfalcon or other seniors.
As to whether having an extension granted stating having a job and planning to live in Quebec in response to IRCC requiring justification for an extension not sure anyone here can answer as this is all new with little or no history on this forum. Although odds based on other posts in dealing with Quebec having not applied specifically for Quebec would seem to be negative at least prior to actually becoming a PR.
Only IRCC of course can answer the question not this forum