If she catches the Dragonborn stealing from the Temple and he or she escapes, she will hire bounty hunters to "teach that thief a lesson." She can also be rescued in one variant of the Rescue Mission quest.
She can be married, and upon doing so will provide a daily income, collectable when spoken to.
Though the dialogue option to move to a new home is available, and she will travel to Riften to be married, Orla will not actually move from the temple of Dibella to a new home.
After marriage, Orla does not have the option to become a follower.
Orla's marriage dialogue options and voicing are the same as for Jordis the Sword-Maiden, (Housecarl, Proudspire Manor, Solitude), with the exception of the follower dialogue options and housecarl/thane dialogues.