Anything posted on Utopian is immediately posted to the blockchain so yes shows up on any other sites that pull all content. You would never be asked or need to replace the contents. If it doesn't get approved it just won't show on Utopian but it makes no difference elsewhere.
For the tutorial, you select the open source project you're writing about in this case 'steem.js' and then, in essence, you are writing a guest post on the utopian website. I'm not sure they would take into account any external content, so at that point, you're just doing another steem.js tutorial which I could imagine a trigger happy mod might shoot you down for duplication (in theory you're not allowed to do tutorials on anything that has been done before)
What you're doing sounds more like it would fit in the development category again. You are creating an OS project/OS better documentation to help people learn steem.js. It's not a clear-cut one though. I've been in the same situation with a website for my tutorials, which I'm hesitant to submit.
Oh awesome, so I really have nothing to lose by posting through Utopian. It might get rejected but it's no different than only posting on Steemit I guess.
Thanks for the help! Have felt a little confused about how to approach posting some initial stuff on Utopian until now.