Well , a Braai is pretty much the South African ( Afrikaans ) word for a barbeque.
Pommies is a word the Australians used for the English, but actually meant Prisoner of Mother England, I am sure you are aware that Australia started off as a Prison Colony for the English ( I guess dangerous Characters breaking out would not have much effect?) I am not aware of any nickname for Canadians, however ,they did, after all get the Rolling Stones to perform a free concert!
And yes, BBQ is a popular flavouring for Potato Crisps and Chicken etc.