A: You're able to do that with out platform. The system is in production ready.
It's hard to give you an answer to how many users it can handle as that depends on too many factors that are use case specific. If you upload no other data, you could register 30K users per month on tier 2 and share 100K requests between them, reading an article would theoretically be 1 request so 3+ per user if you had 30K users.