New Family Member?

Stephen (whom supposedly does not much care for cats) has taken in a stray. Weber, as he calls her, is seen here playing with a moth on the front porch. She just showed up this week. I have already given her flea treatment, wormer treatment (she looked horribly skinny), and food. She can't come inside, though, or my cat would kill her. I wanted to name her Ferrel, but I suppose Weber is cute, since she hangs around the grill.
I want to be extra extra sure she doesn't belong to someone before we get her fixed, but I don't want her bringing more homeless cats into the world to starve either. If she has owners, they need a solid flogging. You can't tell from this pic, but she is so skinny she looks like someone ran over her belly.