I really can't remember if calculator is allow or not. I know it's only few months ago but I started to forget already.
You will be doing the test in the collector division, and the test isn't hard. Just lots of simple math problems that you have to read carefully. Interview isn't hard either. The questions you have there are in the right track and just need to prepare some answer and give some examples from your past experience.
I am not sure if they changed the testing location. If it is the same location of where I did the test, it is not a simulation of the actual booth. It's just busy because other collectors and operators are walking and passing. I think what the HR meant is the training that they will give you is a simulation of the actual customer and booth.
I just have to say subway is your best friend and your new home.
Best of luck with your test, if you have worked with cash in retailer before, you will do fine in the test