1. Except for quebec, u can land anywhere and complete the formalities of the 2nd & Final Stage of our Immigration process at that POE.
2. In fact, landing u can do it at Quebec too, but need to move on from there to another provice for completion of the formalities. But, personally, I'd recommend not to land in Quebec, as that will, undoubtedly, add on to your worries.
3. Ditto for PNPs. But it is good to land in one's province, in PNP cases.