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I agree with George _"Wordpress 301 redirects the links from the non-www URL to the www URL so your link juice should still flow to the new URLs and the shared links will still resolve to the right page" _in the long run this will conserve you link juice.

If you're using Yoast, it will set up rel=canonical automatically.  That's not a bad thing, it's just letting you know just to give you a heads up.  Don't worry about that. I think it's fine to promote.  One thing I would do, just to make sure your 404 errors are taken care of, it install webmaster tools (if you haven't already) and make sure no other 404 errors come up. Looks good though!