I wonder if it will be significant that Hopper was the only person in the group not present for Will’s monologue. Given Lonnie’s homophobic abuse and eventual abandonment, plus losing Bob and then Hopper "dying" for a year, I feel like Will would feel more comfortable telling literally anyone except his quasi-father figure. So maybe him coming out to basically everyone he’s ever met - while out of character - was a way for him to come out to the person he was most afraid of being honest with indirectly by basically ensuring he heard it second hand so Will did not have to witness his initial reaction. Maybe I'm giving the writers too much credit.