Anagram on the side of a van...is it a clue? Or is it just something to throw us off? How does a 6 year old boy imagine a smoke monster, and draw it in crayon for Richard to see when he comes for a visit? The boy got two of the three items correct when Richard tested him, not too shabby if you ask me. The fact that Richard had items that belonged to Locke as leader of the Others is a clue that Locke had lead. But in the story so far, he has not really had a chance to, has he? He started jumping through time the moment Ben turned the wheel. And upon meeting Richard again in present time, they instantly go on a voyage, no leading going on there, or a chance to sit down and read a good book, like the one called "The Book of Laws". So how did Richard get items belonging to John Locke, unless those items belonged to another man reincarnated as John Locke.
All other stories of reincarnation tell that the person who is leading a new life has no recollection of his past life, and if he does it only comes in dreams and fleeting images that don't really tell them much. Maybe the reason John knew the island so well is because once he crashed on to the island memories of his past life began to come to him. Maybe John has been MM since the day he was born.
Just another idea. I can trash this theory myself, and take it apart piece by piece, but it is something fun to discuss or think about.