Primarily, I would be looking for two people to be filling in the roles of two very important people in Locke's life. When her family was killed, it was by the hands of two people. 

1. A Grimm Troupe member who used her and her family as hostages.
2. A Etherium Council member who disregarded their lives to try to secure an arrest.

Locke doesn't seek vengeance in the case of bloody murder. Instead, she just wants justice and finality for her family's death. As such, the two people don't need to fit any criteria in regards to their views and personality. That can be developed over time and conversation. A few bonus points is that this event is also responsible for the scar that is on Locke's eye. It's a painful reminder of her inability to do anything in a perilous situation. 

3. A teacher. 

Locke is training to become ready to confront and potentially fight the two people she has swore to bring to justice. Yvel's a wonderful teacher, but Locke would also want to find someone that can help her with her swordplay. 

4. Friends that can challenge her shy and evasive personality.

This is fairly self-explanatory. Locke's trauma has merged into her established shyness. She's scared of the world and the people in it, but she's not closed off to it. The young woman will need someone to be able to bring her out of that shell. She'll need people that will help push her to heal.