I think he thought he knew the password since it was supposed to be En's birthday. He only found out later on that the "birthday" En meant was the date he decided to live as an omega which was the day Habaki got hospitalized
He knew from the start the day alpha got hospitalized he read it that's why he mentioned "you did great work at hiding I still believed in your words that's More En like"
Riku was someone who had a hard time expressing his feelings, the only way he could express himself was through his paintings. But since he became unable to paint, he had no outlet to let out his feelings, so Minato tried to make him do it through sex.
There is no way they are
Right?
RIGHT?
they aren't xD