First time I hear of "Scarlet's Return" quest not gonna lie, granted I've no intention of releasing the harpy from salvery so maybe that's why? I do to her same thing I do to all my slaves, basically:
Step 1-Enchanted Mystery Kink to make them love being my slave & getting milked as Dairy Cows
Step 2-2 Biojuice Canister to turn them into slime, TRANSFORM THEIR BODIES HOWEVER I WANT, then change them back into perfectly sculpted sex goddess.
Step 3-Use Arthur's watch to make them all bisexual so they have the hots for my character & "get along" with their fellow slaves.
Step 4-COOM time!