The team seems to have a bird motif, similar to Team RWBY's fairytale motif and Team JNPR's motif of mytho-historical figures who disguised themselves as the opposite gender. Each member's name is synonymous with or similar to the name of a bird.
Furthermore, the birds lend credence to the possibility this group shares a heraldic motif. While the cardinal is an obvious allusion to the religious station of the same name, the others (Thrush, Lark, Dove) are figures which were typically used on heraldic shields.
As revealed during "Forever Fall", each member of the team has eyes which are all a shade of blue.
Sky and Russel's eyes changed from blue to brown in Volume 2.
The team also appears to possess a medieval or knight theme as each member uses weapons that bear a striking similarity to many medieval weapons.