Re: About those simplifications.
The prunig of -our to -or in the USA, and many other simplifications, was down to Noah Webster, and extremely recent in linguistic terms. It's not a bad simplification, but it's not as if the British suddenly decided to 'look French', the 'u' is more likely vestigial from the development of the mongrel language that English is. And being a mongrel is what makes it so strong and widely adopted in various forms.
Spelling, and uptightness about it, is a fairly modern phenomenon. Famously, Shakespeare spelled his own name 14 different ways. Interestingly, USA is slightly more fixated on it than UK, here 'Spelling Bees' just aren't a 'thing'.