Rivalen - a kindred spirit! James might well run into him on the occasions that he is also in the city. Because he will likely be in a bar at some point.
Siri - James would probably find her weird and unnerving. In a word, he will try to avoid her. If she ever sees anything about his past, he will likely walk away. And then have horrible, horrible nightmares and fantasize about plucking her eyes out... He can be a little creepy, himself.
Esther - Will annoy the crap out of him. If she is only a tease with the flirting, he will probably not be incredibly nice. If the flirting leads to other things, though, he may actually not be too irritated with her after all.