There are PLENTY of straight men who wear lipstick/nail polish and have long hair.I think Haku is gay.
1. He would do ANYTHING for Zabuza
2. He wears lipstick
3. He grows his hair out that long, when obviously Zabuza cuts his hair
4. He poses as a girl
5. He wears nail polish
All of what I listed are just decisions he makes by himself. He can change any of these if he wanted to, so I don't just think Haku is gay because he has a feminine look to him, there are other reasons.