This evening, there was sound of cat aggression in the porch. When I looked out, I saw an Indy-like cat scuttle away while Ginger was looking on from atop the car. I think Vincent chased her away.
According to my husband, this is a pavilion cat who is bullied by Rosie. She is fed by Francis at the pavilion and used to be Rosie's friend previously. I think she has already been spayed though I cannot be sure. She's a black-and-white cat, and looks like Indy from behind.
Looks like she has grown braver?
Didn't manage to get any photos, though...