Honestly, unless one make an official statement regarding their sexuality, wich they usually don't, it's all speculation. I just enjoy the yuri shenanigan without thinking too much about behind the scene.
I understand both sides I think. Some people feel that the slow-burn is working is, others feel like it's not getting anywhere / even by slow-burn standards. Both are valid imo
^ nah, the "cousins" (as in, they are only cousins in American dub, not in the original. The American publisher tried to make them not gay by making them gay and incestous) are Haruka (Sailor Uranus) and Michiru (Sailor Neptune).