The new werewolf character is stella and the other two are isaac and kraden (muhahaha long cut scenes gooooo!) Judging by her color and that she is a werewolf Stella is likely the 2nd Jupiter adapt of the game and meaning that, along with harmony and the shadowed new character, there will be 3 girls and 5 boys just like in Lost Age
Translations from Gamefaqs
Stella
A human beast race that has mutated since the Golden Sun Effect. Excelling in the 5 senses, she can read the minds of her company and sense unique smells, and is able to use visualized Psynergy.
Isaac:
The leader of the Warriors of Vale who caused the Golden Sun 30 years ago
An earth adept, the father of Matthew/Muuto. He built a cabin on the Goma Hill opposite the collapsed Mt. Aleph, to observe and watch for any strange occurances.
Kraden:
A scholar of alchemy with extensive knowledge from his travels around the world
The teacher of Crown/Rief, he travels around researching alchemy. Previously, he had traveled together with the Warriors of Vale.
In the psynergy section they added move, frost, pound, and slap(?) to the outside of battle psynergy list