To your questions:
1 - Irrelevant.  We don't have a US-style electoral system in Canada.
2 - I don't think so.  A threshold is akin to the losing candidates garnering votes that are discarded in FPTP.
3 - Yes, it does.  So?
4 - In theory yes, in practise no.  More often than not, the winning candidate represents every *like-minded* citizen in the riding.
5 - Correct.  This is one reason why the MMR form of PR should be rejected.