Hello,

you are in the remote course for one week followed by the exam on Friday. Yes, the WebCam must be turned on.
As far as I know, anyone can book this.
I have made you even without deep Jamf knowledge and passed.
Of course you should have a rough idea of MDM.

Greetings

Yes completely open book, the jamf exams simulates a real life situation so you can use workbooks and the internet to search for answers.
You will only get tested on what's covered on the course and there are no trick questions. The weeks training will equip you with all the knowledge you need.
Ive you passed the Jamf 100 exam and understand the Apple & MDM concepts then you shouldn't have any issues passing.

Anyone recommend articles/outside resources alongside JAMF 200. I want to learn as much as I can before taking the course so I’m well prepared for the exam and I end up don’t failing and losing my money. 

If you have a Jamf Subscription, check out the Training Catalog.

Jamf Online Training Catalog

Look at the videos for new Jamf Pro Administrators (both iOS and macOS), especially the ones about Policies, Profiles, Enrollment, Smart/Static Groups. 

Take good notes, ask questions if you are stuck on something (dont feel embarrassed about it - you're there to learn).  The instructor will provide you everything you need in order to pass the exam; they may not give you the answers directly to exam questions, but you will go through scenarios on exam day that you covered during the week.  As @Tribruin suggested, check out the Jamf training catalog and study up before your class.  When you get home, hit up the training catalog again for additional review before the next day.  You will do fine!!!