The Queen's representative to Canada is the Governor General. At the provincial level, the title is Lieutenant Governor (pronounced LEF-tenant). Note that since both titles represent the Crown, they are considered equals. The Lt. Governors are not subordinate to the Governor General.
This depends on the situation and place. In many places, the Queen's representative is the Governor General at federal level, and for provinces it is Lieutenant Governor and for territories it is Commissioner. There is no representative for Municipal level
I imagine they remain silent during the ceremony. Speech isn't suitable for them at that moment. Monarchy today is mostly representative, the new Kings and Queens do not have power on the decisions of their countries' political issues. Such decisions are taken by the prime minister.
The Queen's representative in the provinces are called Lieutenant Governors. Their counterparts in the territories are called Commissioners, however they are not technically the representatives of the monarch but still act in a similar capacity.
machiavelli thought of the nobles in a different point of view. he didnt agree with the kings and queens and their political thoughts. he was an amazing writer who wrote about how the king and queens should think and how much better they would be if they thought the way he did.