Hi Rahul,
let me try to answer at least part of your questions:
1. When I took the exam I was facing the wall, and there was a window to my left, but it was behind me. The check-in process was fine for me with this setting.
2. Honestly, I don't know. I would try to ask it to PearsonVUE.
3. Once you pass the check-in procedure, the audio/video registration begins, so you should wait at your workplace for the exam to start. However, in my case it didn't take long: in fact, as I realized during the break, I must have started the exam a few minutes earlier than scheduled.
4. After you submit the first part of the exam, you will be prompted for the break to start through a pop-up window on your screen. No need to chat with the proctor for that. At that point you can either decide to start the break (in which case a countdown timer will start) or skip the break, and move on to the second part of the exam. In case you opt for the break, you will have the opportunity to stop it and resume the exam before the end of the 10-min break.
5. I don't remember such a question specifically. However, I do remember that the systems asks you twice whether you are ready to submit your answers. This applies to both parts of the exam. This reassured me in a way, as there was no chance to submit either part of the exam by mistake, before completing the review.
6. I think you can—as long as you remain in view of the camera and do not 'hide' your face behind your hands. I don't know about the glass of water on your table... I think you are not allowed to drink during the exam. In my case, I had a clean desk, and drank some water during the break, in another room.
Hope this helps,
Gabriella