Actually I think it's alphabetical, but yeah there is no way to change them as far as I know...
No it's not, that's why in mine Android Central is third in the list after Youtube and Jeep Forum, and accuweather is at the bottom. It's listed in the order you add them.
Is there a way to delete some of the bookmarks that were already in?
There is a nice program called Bookmark Sort and Backup that will rearange the bookmarks, even in the Bookmarks widget..