Not super related but I almost didnt get my PhD dissertation reviewed because while at LSE I insisted/demanded using neither British English nor American English, but Canadian English. In the end they caved and published it in my preferred spelling :).

Wow thats so petty but ultimately I get it if theres a spec that has to be satisfied. Good for holding ur ground tho :) U are definitely stronger of will than I would be similarly

Not controversial in itself, but in highschool we found it extremely weird that our former rugby player Headteacher had done his Masters thesis on medieval rabbit farming techniques. He was an absolute slab of a man, it just didn't fit.

This might sound shocking, but I haven't encountered any, and would have to search how to do so.

Are you describing a mix between British English and American English, or something else that is uniquely different from both?

https://en.wikipedia.org/wiki/Canadian_English

Canada's official spelling is a unique mix as well as some of its own traits.

We add 'u' to colour, and centre is re, like British English. Or defence instead of defense. When we table bills it means to add them to the agenda, not pause them.

We use 'z' instead of 's' in colourize, but call it 'zed'. Its aluminum and 'gynecology', not aluminium and gynaecology.

We have our own words like 'tuque' instead of beanie.

Eh isnt just a joke, Canadian english has innovated English by adding a sentence final pragmatic particle (a word signifying the sentence is a question). Many languages have this while English needed a raised sound. Canadian added 'eh'. Its similar to 'ma' in Chinese or 'ne' in Japanese. Mind you this last one never made it to my dissertation.

I knew that we spelled differently, but wasn't sure that Canadian English had an official definition.

By the way, I speak it touque.

Also by the way, regarding your final point, Sesotho (a Southern African language) adds "na" at the beginning of sentences to make them questions. Other Bantu languages (like Zulu, Pedi, Xhosa, etc.) probably do the same.