Those lists of "famous people like us" are nearly always dubious, and the dyslexia one more than most. Lennon published a lot of stuff in manuscript, and there's nothing dyslexic about any of it. Deliberately eccentric in a way that would drive a rigid teacher up the wall, yes, but it never comes across as being something he couldn't help. Look at this manuscript, intended for private use - the words are not simple to spell but they're all spot-on

http://www.finebooksmagazine.com/issue/200903/graphics/auction/9-lennon.jpg

whereas here he is in full creative-spelling mode for public consumption:

http://news.bbc.co.uk/media/images/40124000/jpg/_40124882_page_220.jpg

And some of those entries are based on no evidence whatever - look at the ones on Flaubert and Agatha Christie. Einstein is a favourite adoptee by advocacy groups; I've seen a few of his manuscripts and they have nothing in common with any dyslexic writing (the whole lot is at http://www.alberteinstein.info/manuscripts/ , but my browser can't access that).

Yeats is an interesting one. That site does make a good case for him being dyslexic. But he was also completely tone-deaf, unable to recognize any tune. Hardly any of his poetry is singable. His mental world must have been very different from most of us.