That cribsheet is detailed to the way our migration worked.
Just rename your account with the GUI. This changes ownership and rebakes all your posts.
So what is left over are posts in response to you. This means that any @mentions are a straight replacement "@paul " for "@paula " and rebake. The only thing you won’t be able to catch is “Hey Paul” or “As Paul wrote”, but these will be self evident from within the context of the posts.