For #1 the key is that Canada may consider you a resident for certain purposes (e.g., immigration) but not for others (e.g., customs, health care benefits, taxes).
For the B4, take a look at the regulations covering B4s:
Who are considered Settlers?
Under customs legislation, Settlers mean all individuals who enter Canada with the intention of establishing, for the first time, a residence for a period of not less than 12 months.
It is important to know that the status of a person for customs purposes is not always the same as the person's status for immigration purposes.
For example,
Code:
Persons coming to Canada for the purposes of employment for a period exceeding 36 months (other than United States Preclearance personnel) are at first arrival considered to be Settlers to Canada even though they may be considered Temporary Residents for immigration purposes;
Persons entering Canada to become Permanent Residents without the intention of residing immediately in Canada are not considered Settlers to Canada since they do not have any intention of remaining in Canada at that time, and will live outside Canada for an undetermined period of time. Therefore, under customs legislation, these persons are considered visitors to Canada, even if they are Permanent Residents for immigration purposes.
You can see the details in http://www.cbsa-asfc.gc.ca/publications/pub/bsf5113-eng.html and http://www.cbsa-asfc.gc.ca/publications/pub/bsf5114-eng.pdf and the CBSA Memorandum at http://www.cbsa-asfc.gc.ca/publications/dm-md/d2/d2-2-1-eng.pdf (especially on page 3)
