I believe Lifnei Iver applies only when there is only one possible supplier of the assur product. Otherwise it’s mesayahu lidvar ha’assur which is drabbonon
Our chasuna videos have separate sections for men’s dancing, with the entire chasuna, and an entirely separate video which includes women’s dancing
I’m not sure how the YouTube issue differs from the sale of women’s only DVDs. Just don’t watch them.