Responses

Cabel doesn't. She's his little sister.
Erich does, because his twin sister dying made him especially resistant to thinking of Hari as his sister. According to the novel, he developed a crush on Hari during his sleepwalking phase, a little before he accepted her as an Ernst. So there was enough ambiguity there to allow for it. (Even then, he never intended to act on the crush, because she needed "family" more than she needed a "lover.")
shocked that eugene's the male lead? well what if i told you-
that erich is in love with hari too?