2. It's as the letter said. You're in a city called Papillon. And yes, you are alive.
3. I haven't seen anyone with that description. Also, I should warn you, even if you do come across someone who looks like that, they may not be the version you know.
4. We aren't sure why the creatures are running around but, aside from Frankenstein's Monster, as I'm fairly certain he's simply misunderstood for the most part, yes. You should most definitely kill them if at all possible. Particularly the zombies. Unless you'd like to become one, of course.
Welcome. My name is Amitiel. I hope that answers your questions. I'll be happy to try to answer more but I'm afraid you'll have to stop yourself from threatening me with violence if you want to know anything else.