I don't know that I see those as issues, unless you're trying to maintain two separate identities on the two websites.

1. If you really are trying to treat your blog on steemit like a blog, and only blog about specific things on steemit, then yes, posting new posts on chainBB would ruin that to a degree.
2. This is bad? What do you mean?

If you really want to separate out your activity of blogging and forum participation: just make a 2nd account, one for each site! :)