Bellemore's siblings were both separated from them at a young age, so while Orion and Miriam are quite close, they're estranged (to varying degrees) from Bellemore. After the death of their pack's leader, the two of them left a few months after Bellemore fled.
Personalities are just vague guidelines! All I'd really ask as far as 'auditions' go, would be to do a small write up of how you see them.
Miriam Anjel - generally carefree and kind & attempted to have some level of relationship with Bellemore.
Orion Anjel - a little reserved than his sister & never attempted to form a relationship with Bellemore. Resents them a little.