From the Fusion Auth website
FusionAuth is the customer authentication and authorization platform that makes developers' lives awesome. You'll get all the features your app needs plus a customizable, scalable solution you can run on any computer, anywhere in the world.
Fusion Auth can scale horizontally via Docker containers. Just throw a load balancer in front of it.
More than 5 minutes, but still very simple.
No, roles are per application.
Not without a license, may or may not cost