Can two people simultaneously watch on a different Netflix account Netflix on two different devices?
That depends on what tariff you have. In the tariff with an account, I think that it is not possible.
Depends on which subscription is booked.
The basic subscription can only one device at a time. The standard subscription can be two at the same time and the premium subscription even 4.
Come on the subscription on what you have completed. With the Basic subscription, no. With the standard and premium subscription, with Premium you can even use an account on 4 devices at the same time.