Yes. You can view the system requirements here: https://education.lego.com/en-us/support/wedo-2/faqs.
FIRST will be providing guidance to teams regarding video requirements for submission in the coming months. Renaissance will share that information as soon as we receive it.
No, there is one score sheet to be used by both EV3s and Spike Primes.
Yes. FIRST will be providing more details regarding this in the coming months.