Who were Canada's allies during WW1? Do these allies include other countries that were considered to be part of the British Empire during the war?

All of the countries which were part of the British Commonwealth were allies during the war, including Australia, New Zealand, South Africa and India as well as Canada.  India was part of the Empire, not a Commonwealth country.  These Allies were formally known as the Entente Powers. They were allied with Great Britain, France, Belguim, Rumania, Russia (until the Treaty of Brest-Litovsk in 1917), Japan, Greece, Italy after May of 1915, the US after April of 1917, Montenegro and Serbia. And of course countries which were part of the French Empire sent troops or support personnel, such as Morroco, Algeria and the Indochinese countries.