I think you’re right in the sense that Meursault is much cooler (in temperature) than Watanabe; but I think at the core, the commitment to honesty and a certain nonchalance—floating along, until events force them to become engaged—are very similar.
I could argue this intellectually, but actually the similarity for me is a feeling. My theatre group did a piece inspired off Norwegian Wood, and a friend of mine is planning to do a play of The Outsider. In both cases, I can see the same actor playing the lead. Just like Cate Blanchett has a huge huge range, there is something quintessentially Cate. She has difficulty, for example, hiding her fierce intelligence (for example, as Sheba in Notes for a Scandal), and always gives a certain grit to her characters. And on this basis, I sense a certain combination of nonchalance, of honesty, of commentary in the characters.
Now whether, of course, someone who likes Elizabeth will like I’m Not There (where she plays a Bob Dylan) is highly disputable and even illogical; but I think, @broase, it boils down to why you like Camus. My gut response is that there is a similar quality with the protagonists, Jeruba doesn’t think so; maybe you can go read the book and tell us if you like it. I hope you do – I enjoy Murakami’s writing a lot!