I am not the most technically savvy so I cannot answer all your questions but I will do what I can. 

I do know that Auto-play is not allowed, so a track in your sig is fine, if it doesn't auto-play. 

As for where to put a thread full of your music, I would suggest the Gallery which is where creative works of all kinds (writing, art, music etc) typically go. But member lounge wouldn't be out of the question either.