I am just a first-year student, so I don't know everything, but I will try my best to answer your questions.
1. The only time scrubs are heavily required is for anatomy labs during the first semester during pre-clinicals. I am not super familiar, but I think that you have to wear scrubs some of the time when you are in the hospital (like in the OR, for example).
2. Scrub color does not matter.
3. You have to buy your own scrubs for anatomy and other school activities like that. But, if you are in the hospital for shadowing, preceptorships, etc. they provide them.
4. Yeah. I have several scrubs of various colors that I use.
Honestly, the school is not super strict on the type of scrubs or color that you have, at least for school-related activities like anatomy.