L never really had a coming out, he just said who he was interested in at the moment and as long as they didn't seem dangerous to him and L liked them, Watari liked them too.
Light was super afraid of his outing and first outed himself to his mom and sister. Sayu was super excited to meet Light's boyfriend cuz she knew Light only picked special people, so she knew she'd like him. His mom was happy that he found his special someone and that he seemed happy (she always had a slight feeling that Light liked boys). His father knew nothing about it for quite some time until Light introduced his boyfriend to the family, knowing Soichiro probably would react very happy- he didn't, but after some time he grew to accept his son's sexuality and was ok with their relationship (he cried some tears of happiness when Light married L).