The highly respected japanese videogame publication Famitsu has provided us with a nice big plethora of Sonic Rush Adventure information, including the official name of the new female character. We can officially confirm her name as Marine the Racoon. The promotional art on the pages also depict another new green torpedo-resembling character who is presumably a henchmen of primary antagonist Captain Whisker.
According to the article, the two recently revealed ‘Zones’ are named ‘Plant Kingdom’ and ‘Machine Labyrinth’. Their bosses are also shown as a mechanized T-rex (For Plant Kingdom zone) and a robot that apparently uses weights to impede Sonic’s progress as he fights to defeat it (The ‘Boss’ of Machine Labyrinth). Tails, as he was in the previous Nintendo DS Sonic title Sonic Rush, will serve as Sonic’s assistant on the DS’ top screen and he will also produce various crafts to travel from area to area across the sea depending on the machine parts Sonic gathers for him.
What we can also gather from the japanese article is that the area where the player sets out from is named Southern island and presumably it is the home of some of the characters depicted in the articles’ screenshots.
Many thanks to Charmander of the SSMB forums for the tip off!