It's really important to manage versioned schema for events and defining rules around evolution of schemas, hopefully with tooling support like via Avro's Schema Registry or Protobuf's forward and backwards compatibility guarantees.
No, it's really not a high number. It's right on the money for 3 years in-the-trenches experience making the move into consultancy -- around $130-140/hr billable, which is what I was billed out at in the mid 2000s as a .NET consultant.
There are plenty of fair use exemptions to copyright. That said, US law is not the highest of moral standards to aspire to. Especially US copyright law. We've been flaunting it online forever, because it's obviously ridiculous and still hasn't caught up with what's fair and equitable in 30 years.