Express Entry or PNP for better chance - CRS less than 400

Thank you for the response. Just a follow-up question.

Is there any mandate to work for the exact same job offer, using which the PR was obtained?

For example: Let’s say me or my husband gets a job offer but we are not happy with the pay package or location, can we still use the job offer to obtain the PR (AND) Can we still enter Canada just for a short vacation, just to see how things are and get the PR activated and return back to USA and have any of our friends ship the actual PR cards to our US address? In this case, we may or may not take up the original job offer, though we used it to obtain the PR.
We could continue our job search while in the USA and then eventually move in using the PR when a good offer and location works out.

Please let us know if this is allowed?

Also, my understanding is atleast 2 years of work in Canada out of 5 years in necessary for the PR to be active AND atleast 3 years of stay on PR is necessary for Citizenship. Is that correct? - In case, does the entire family need to be living for the specified time period in Canada or just one of the applicants?