All of these above are great questions to ask and asking them will not just give you answers you need to make an informed decision but also demonstrate to the interviewer that you are not just blindly jumping into anything.
I would also encourage to be observant. You can gauge a lot from non-verbal conduct around you.
Are you interviewing only with senior staff who are possibly not the decision makers? Is your interviewer checking his email constantly during your presentation? Did you have to wait before the interview? Do they know your work beforehand and are prepared and genuinely interested?
Also the general feel for the place will tell you a lot. If people are unhappy, you can tell right away.
I have had interviews where, when I entered the studio, I felt a cold shiver and knew, this was not a good, constructive place.
As designers we are passionate people who are putting their ideas on the line and are being judged every day. It is emotionally exhausting. A good, constructive team and environment is essential and I am sure that if you visit the firm, you will be able to tell even without asking the questions out loud, if its a good one.