So a relationship between a female-bodied nadleeh (woman acting as a man) and a woman would not be considered a homosexual act. Now if two men or two male bodied nadleeh got together then they would be considered homosexual.
On the very last page of Navajo Culture research is a diagram and information that describes types of kinship in two different areas. There is two charts that are listed from top of the kinship to bottom of the kinship. This is based off of a research study that was taken place, it was stated that it is more accurate than that of others that have been place out there (A note on regional variation in Navajo Kinship