Well, it would be much more interesting and economical since cosplay is a kind of expensive activity. And Sephiroth cosplay is quite popular and impressive, any of us would need to buy the wig for it, as the same time, some of us must think about that to cosplay the other character with this silver wig without spending more money on the imitation after portraying final fantasy Sephiroth. But who has the similar hairstyle of Sephiroth?
Umm, I try my best to recall my memory and finally, I figure out Akifusa Keikain from Nurarihyon no Mago or Nura: Rise of the Yokai Clan, he is a talented onmyouji and is one of the members of Keikain House. As for his appearance, he has long white hair that is aimliar as final fantasy Sephorith. Maybe because of my lacking of knowledge of the characters of manga, anime, video game or other media, Akifusa is the one close to Sephiroth most at this moment. Yeah, maybe you guys have better idea.
There are also many other characters have long white hair, such as Ukitake from bleach, Agni from Kuroshitsuji and Inuyasha, it seems that each of them has snow white hair, plus different types of bangs and styles.