If so, does the content that I posted on here stay on here under my name or does it show up as "deleted user" or something like that?
Even if you delete all your posts you should know that everything is archived and backed up in bitcointalk forum with multiple services from LoyceV and Ninjastic.
You can't delete topics that you created even if you wanted, only way is to ask moderators to do this for you, but like I said archives will remain.
If you wanted to hide your real IP address you should use earlier something like Tor browser or vpn services, but now it's to late for that.