Well, its Japanese name is Sheimii. Serebii, Jiraachi, Sheimi, Manafi, Bikutini.
It was, but only in Japan. And only once, IIRC.
I find it funny when people give that as a justification for Phione's existance. Manaphy come from blue Eggs. How does it laying white Eggs explain anything? As far as I know, in Pokémon Ranger 1, it is explained that the blue Egg cannot be hatched in Fiore because it's a warm region, and thus should be sent to Sinnoh somehow, as it's a colder region and only there can the Egg be hatched. From this, we can postulate that, once the Egg arrives and hatches, Manaphy is ready to lay as many Eggs as it (or Ditto...) can, but they're all white (and with a Phione inside) exactly because of Sinnoh being colder. Those Eggs, however, just like the blue ones, can only be hatched in cold regions. The reason Manaphy is so rare is because blue Eggs can only be laid in warm regions, while hatched in colder ones. Phione doesn't have this restriction, and thus is more common (or should be), but it cannot evolve to Manaphy because it's kind of a "mutated" Manaphy, and thus is technically Manaphy already.
However, it wasn't necessary for Phione to exist to "explain" anything. Game Freak could have just said "oh, Manaphy can only lay Eggs in warm regions as its reproductive system atrophies in colder ones lololo" and call it a day. See? No need for Phione. They did it so merely because they wanted to. And see, they didn't even fully explained why does it work this way. Silly, silly Game Freak.
...Maybe I got things mixed up and it's actually Fiore the cold region and Sinnoh the warm one, but bear with me here, I never actually played that misson from Ranger 1...
Brave Heart is Ho-oh's theme since HGSS, go read the translated lyrics and see how right I am ~__~