I don't understand why people think Nanashi no Asterism ended with no one getting together. It's not explicitly said, but everything points to at least one yuri couple in the end.
Every triangle can't end in polyamory. And all yuri crushes don't mean they are gay and will necessarily end up with a girl.
As for Robert, I'm not sure they need to be labeled with the transgender tag. They say themselves to be "half and half".