Re: smoking indoors?
I've hardly smoke outdoors, and it doesn't linger or stick to things like cigarette smoke. In that sense, you'd be fine - especially if you are keeping the place opened up. That said, if it's your parents house and they are OK with outside but not inside, don't do it inside.
And yes - the coal thing. A sure way to get yourself in a heap of crap, lol. IMO, it's not worth it, but you could get away with it fairly easily.