Can I use the GetOriginator* methods in the Notify* events?

You can call GetOriginatorProcessId, GetOriginatorProcessName, and GetOriginatorThreadId during notification events (since such information is static, and can be stored safely), but you can't call GetOriginatorToken (the token cannot be stored safely; notification events are fired asynchronously, so it's possible that the token could become unavailable/invalid before an event has a chance to fire).