You’re referencing the public MOOCs (massive, open, online courses). They’re offered by many schools around the world. Those aren’t for credit and they aren’t part of any undergraduate program.
There are professors who [record their lectures](CS 101: Lectures) so students can go back to review them while studying and professors who [post videos explaining answers to exams/problem sets](http://rabi.phys.virginia.edu/1050/2015/home.html). Special panels and speakers [often get live streamed](https://www.youtube.com/watch?v=gqWKSvqKRrA), too. Is that what you are referencing?
OP, UVA is fabulous in the area of politics and government. You’ll have many options to consider if you come here. However, all three of your choices are excellent and will provide wonderful professors and opportunities for jobs/internships/research. Think about where you will be happy and comfortable. That’s where you are most apt to be engaged in the classroom and in the college community. Good luck!