Perhaps hackers could modify the data displayed by your website, but I doubt that a website could be so insecure that it would be dangerous to people visiting it with any sort of modern browser. Browser makers are quick to eliminate that sort of vulnerability in their browsers.
I used the "optimal team" list on your spreadsheet more than anything else. I find the "optimal team" section interesting and useful for learning what my team should look like if I want to do better.
Although, having said that, instead of trying to pick a team based on pure mathematics next time, I'm thinking of picking a "team democracy" that will not try to be mathematically perfect, but instead represent as many countries of the free world as possible.
Next time is going to be coming pretty quick if I'm not mistaken. Due to the delay of a year, and the fact that next winter will come half a year sooner than next summer, I think we are only six months away
from the next