Latios and Latias/Latios and Latias

Japanese VA:  Ebara Masashi (Latios), Hayashibara Megumi (Latias)

Latias (the smaller, red sister) and Latios (the larger, blue brother) are the protector gods of the water city of Alto Mare.  Once upon a time, the two stopped a rain of darkness from destroying the city.  They also created an orb, the Shizuku no Kokoro ("Drop of the Heart") to keep the city prosperous and to prevent it from ever being flooded.  Because of their status, the two pokemon reside in a secret garden and are hidden from the public by both Kanon and Bongore. 

Both pokemon have the ability to alter their appearance at will.  Latias, the more playful of the two, often disguises herself as Kanon to allow her to freely roam about the city.  The two pokemon also have the ability to make themselves nigh-invisible (to hide themselves from enemies) and are able to see what the other is seeing at any time. 

Annie and Oakley/Lyon and Zanna

Japanese VA:  Kanda Uno (Zanna), Shaku Yumiko (Lyon)
Pokemon Captured:  Zanna--Eefi, Lyon--Ariados

Zanna and Lyon (pronounced like the American name Leon) are two famous thieves (who, contrary to popular belief, have no connection to the Rocket-Dan) who are after the "Drop of the Heart."  The two thieves are rather famous in the world of thievery, and even lowly crooks like Musashi and Kojirou know of their exploits.  Both thieves use a variety of high-tech gadgets to to achieve their goals, and one gets the feeling that they have a high rate of success.  When the two aren't looking for the next high-profile item to steal, they're usually seen grooming themselves.

Bianca/Kanon

Japanese VA:  Origasa Tomiko
Name Meaning:  The word kanon (it can also be spelled canon) is, according to websters.com, a "composition or passage in which a melody is imitated by one or more voices at fixed intervals of pitch and time."

Kanon is the young artist who Satoshi meets in Alto Mare.  She has befriended both Latios and Latias and even allows Latias to borrow her form so that she can go out and play.  She helps her grandfather, Bongore, protect the two legendary pokemon. 

Lorenzo/Bongore

Japanese VA:  Gucci Yuuzou

Aside from being Kanon's grandfather, Bongore is the curator for the museum located in Alto Mare as well as being a boat maker.  Bongore helps protect Latias and Latios from enemies and he seems to know a lot about the "Drop of the Heart."  Bongore pretty much takes on the role of Captain Obvious, explaining all the major plot points for the movie's audience.

Ross/Rossi

Japanese VA:  Yamadera Kou'cihi
Pokemon Captured:  Whaleko

Rossi was a participant in the water race held during a festival celebrating Latias and Latios.  Although he lost to Kasumi, Rossi was a good sport and gave Satoshi-tachi a tour of the city.  He introduced them to the story of the two legendary pokemon before dropping them off at an ice cream parlor for a snack.