Re: should i join this band??
Your in a tough spot. I know, been there. It sounds to me like your very determined to reach your career goals. That's good. Stay that way. Reaching your career goals doesn't mean you should have to sacrifice your musical ambitions. It's all a matter of finding a balance in your life and finding it by setting priorites. These guys should be able to understand that. If not then I say their making your decision for you. Don't worry. Something else will come along. It always does as long as you go and look for it.
As far as the smoking/drinking/drugs thing goes, I think the only thing you should be concerned with is that their not doing it on your time, hindering the practice time. That's always been my take on it. Do what you want on your time at your place but not on mine. Think about it. Your practicing, loudly, and some neighbor complains about the noise and they call the cops. Your string section just finished smokin a lefty and the room smells like a skunks rear end. Suddenly, the cops knock on the door. Do you want to be sitting there? Oh, there goes that career. Just a thought.