Congrats folks.
For the math's assessment, don't be too worried. It's short, 4/5 questions designed to take a couple of minutes each. Expect a True/False of some sort, some probability, some introductory calculus of some sort. That's the ballpark. It's just another datapoint, I was admitted and I did not answer every question correctly. There is also a maths placement test in the first week of the program (there are two summer maths courses, normal and advanced). The choice is ultimately yours, though.
This year, a coding assessment was added. It'll be hard (if not impossible) to find information on it, as it hasn't been done before. As a result, I don't expect it'll be overly challenging for folks familiar with code. For us, and potentially for this class too, there is a coding assessment in the first semester anyway. Being programming literate is not a requirement for the program, but they like to know where people stand.
Over-admission (200 down to 130) is due to people going elsewhere. Don't think there is a single program out there with 100% matriculation. For us, there was only one batch of interviews, where people were interviewed in London/Paris/US/Asia/Skype and so on. I'd say the figure of 25%-35% of interviews leading to an offer is pretty close.
Good luck.