Hi Victor,
Unfortunately that is a browser bug in the way javascript arrays are sorted. We are delivering the list correctly sorted in json but in Chrome/webkit browsers it doesn't sort correctly. It does sort correctly in IE and Firefox.
Before you edited your post you asked also about the h1 mapping to h3, maybe you already found the answer but I just updated the article Customizing the Editor Toolbars with a note about why we do that and how to change it if you don't like it.
Thanks for letting me know about the demo site I'll go fix it right now.
Best,
Joe