Rinoa definitely has two Brown genes. Because of this, no main character can be Rinoa's daughter or son. No one. No matter what, they would recieve one of Rinoa's Brown genes and have some shade of brown eyes.
Again, Rinoa can not be any main character's mother. It doesn't work.
Edit:
Selphie and Seifer having green eyes doesn't change very much. It's still impossible for Selphie to be Rinoa and Squall's daughter and for Rinoa to be Edea and Seifer's daughter.