I don't know musical influences on him. Literary influences on Mishima include Nietzsche, Cocteau, Oscar Wilde, Marquis de Sade, Kawabata, Akutagawa, etc.
Weird thing is that Mishima wrote a few comedies, and they are hilarious and hysterically funny.
I was looking at one at Barnes & Noble the other day, called
Life For Sale, which looked pretty hilarious, quite the contrast from the über-seriousness of
Sailor. Oddly it was the only Mishima they had. Maybe what I'm picking up on is the Nietzschean influence; I don't know, I haven't read any Nietzsche since high school. I ought to do something about that. As for Kawabata, I recently bought his
Snow Country (on your recommendation) and look forward to reading it too. Of the three Japanese writers I've read recently, Mishima is the first one whose work strikes me as a wholly Japanese phenomenon, and I kind of hope to find something similar in Kawabata, even if his work itself seems quite different. There's another Japanese writer I'd love to read, one of these days: Jun'ichiro Tanizaki. But I've got plenty on my plate for now... Very grateful to be discovering so much excellent literary fiction these days.
Edit: Finished
The Sailor. What an ending. That was definitely one of the more fucked up books I've ever read, but my interest is definitely piqued and I will be reading more Mishima.