The following spellings have been actually witnessed all over the Internet, newspapers and magazines. They are all wrong ways of spelling 'Keanu'.
And perhaps most puzzling of all, 'Canoe'. It doesn't even start with a 'k'. Some people claim that they call him 'Canoe' because of his resemblance to wood, but we fail to see the supposed resemblance. (For further elaboration on the subject, please see Keanu is really just a plank of wood and Keanu is really just a tree.)
Which brings us also to the issue of pronunciation. 'Keanu' has three syllables, and is pronounced 'kay-ah-nu'. At current estimate, about 70% of fans and 90% of non-fans get it wrong. This includes people who should know better, such as interviewers and TV announcers.
The most common mispronunciations are 'kee-ah-nu' and 'kee-en-nu', and this is mostly the fault of people who watch interviewers getting it wrong and then decide that it must be the correct pronunciation.
Keanu and the Hawaiian population both beg to differ.
Meanwhile, these are all wrong ways of spelling 'Reeves':
We hope you learnt something useful today.