Nope. Sims appear to have infinite plasma/blood which could be so that vampires have an easy way to replenish the thirst need or so that Sims couldn't accidentally be killed.
Use you vampiric drain spell against him. It will heal you and harm him simultaneously. If you are low on magicka, use the Equilibrium spell found in Labyrinthian Chasm and...
When you are a werewolf you are resistant to all diseases, but with the Dawnguard DLC you have the option to become a vampire, however you won't be a werewolf...
No, they will usually give you a chance to cure yourself from the vampirism curse and give you a couple of days to do so before they start attacking you.
I don't think it matters whether you fight Bowser before getting all the stars or not. As long as you have 120 stars when you defeat him, you'll get Luigi.
You will first have to change your fairy Sim to a normal Sim using the potent cure elixir or the "ask forsake the fae" action with a significant other, then...
