I posted a question a few weeks back about inserting canonical and descriptions into blogs, it should be instructive.
I inserted them directly into blog posts in the HTML view. They remained in the body but were otherwise fine. While I like WordPress and have at times been exasperated with BC I will point out that WordPress doesn't natively handle canonicals or descritptions either.
To support Mary's comment, for the love of god don't every publicly post (link to) your development URL.
I know in a recent video Matt Cutts of Google said to use dashes as separators not underscores, and I have adopted that but I assure you it makes no difference. I wrote a post that used the system generated underscores about the pros_and_cons_of_the_new_google_privacy_policy a few months ago, it's traffic didn't suffer from having underscores instead of dashes; the bots were able to parse it correctly.
My blog templates have meta descriptions (but not canonicals although I am reconsidering that) and I'm not thrilled that if I insert descriptions into posts it will mean I have a few pages at any time that have more than 1 description tag (one of which will be in the body) but search engines are smart enough to detect synonyms and sentence structure when looking at duplicate content and to generate description snippets out of body text rather than solely for the description tag, I think they can sort out 2 descrption tags on the same page.
There are things that can be improved but it's not serious enough that I worry about it.
-Adam
