So ive got an assassin, and its gunna be great dont get me wrong, but I was thinking, boss fights where your directly engaged with no option, is sneak possible?

I was thinking i could get the warewolf disease, and then just release the beast ( i know its once a day) and just slay bosses, Is it neccessary?

Id be werewolf up to level 30 if you really want. Past that point its usefulness dwindels as you'd be better off just using your weapon and armor. It should be managable without lycanthropy though.