Ignorance triumphs again? This story first appeared two days ago, and if memory serves me right, its orbit does not meet the requirements of the definition of a planet.
Could well be so, but if so, Sky and Telescope isn't immune.
Not likely. 2003 EL61 was discovered yesterday, and these other two objects were published in response to 2003 EL61 today.
2003 UB313 is interesting in that it is a lot more planet-like than either Pluto or these other objects. It is significantly larger and is not in a resonant Neptunian orbit. However, it also has an inclination of 44 degrees.
Something else worth noting about these objects: they all give off noticeable water spectra. They may be big, but they are also apparently covered in water ice. This has screwed up the albido estimates used for initially sizing them, making them seem a bit larger than they are.