Anna's Spark profile is set to match her with both men and women, despite Anna's apparent exclusive interest in men. It makes sense once you realize that Ashley created the profile on Anna's behalf. Ashley was just starting to realize that she was in love with Anna, and was probably testing the water to see how she reacts to "accidentally" matching with other women.
The main reason the good ending works out in your favor; You convinced the Simulacra that humanity has hidden depths in their hearts... By pretending to be something it understood perfectly. Not Anna, however. You pretended to be The Simulacra. You proved to it that humanity had the capacity to join it of their own volition, and so now it can tempt them to its side rather than merely absorb them, and expand its influence even further.
