Your first example "donate / donor" is a difference between two different words. As far as I am aware these words have the same meaning and spelling everywhere.
Your second example is the name of an animal, a "lemur". Again, the spelling is not different anywhere. There is no word "lemour".
I suggest you write your sentences and post them for correction. If you need Australian spelling, then say so. If you can only find US or UK spelling variations, then the UK version is more likely to be the standard one in Australia, in my experience.