I’m glad to hear your company is seeking legal advice, since you really need a professional’s opinion on the liability questions.
I don’t have any legal answers, but I would suggest you trust your gut. You seem, understandably, uncomfortable with the level of safety, and the uncertainty surrounding what would happen in the event of an accident. You have the option of telling the creative director you will not attend rehearsals until these issues are cleared up. If the rest of the management team can back you up on this, framing it in terms of a professional company needing to operate to certain standards, all the better.
Can you get a specific timeline from the attorney the company is consulting, as to when they can get you some answers? Maybe the director will be more reasonable if he knows that he will be waiting three days, rather than three weeks.
I think KMC’s advice to seek independent counsel is wise. If you’re worried about the expense, ask around among your family, friends, and colleagues, and someone may be able to recommend a lawyer who could answer enough of your questions for you to feel comfortable.