Is it possible that one person orders several cards ( I mean physical cards not virtual ones) at the same time?
2 cards (virtual + plastic) in each currency (USD + EUR) per account.
What about business account? Is it possible that a business account orders dozens of cards?
It works in a different way. If you have users you want to have cards and they don't have accounts in the system, you can send them money to create cards to their emails, they receive a link that lets them register, they get the money you sent them in their wallets and proceed with ordering cards. Later on you can send money to these cards via API from your business account.