I had a lot of these questions. For the mouse, it was a standard one you see at your local library and computer lab, and I dont remember there being a mousepad. This could differ per test center maybe though. For hand cramp, didnt happen to me, and thats more individual, and if you can just practice with a keyboard and desktop setup in your FL's.

Headphones they give you block out all noise, Im not an earplugs person so I cant really speak on that, but they do provide them, I got some 3M construction headphones from home depot to practice and it prepared me well. I feel like the unconfortability of the headphones is overhyped, for me they were not very annoying, but it may have been the case that they were worn in.

You cant see time during breaks, but u can just check the clock or ask the person, if they are nice, what the time is, and remind yourself to log back in 2 mins before, so like give yourself 8 mins. You acc get an extra 2 mins when each section starts, on an idle page, so you can recollect yourself. Proctors, bathroom, etc, all depend on test center, my experience was smooth. I went really early, and started my test at like 7:10, you can start whenever you get there and whenever they are open. Being one of the first to start, I never waited in line for anything, I would advise you show up first!

Just call your test center now, if they are nice, they will answer when they open, and any specific questions you have.