A Spring (reactive) programming model for Serverless?

As a newbie to functions, serverless and Spring ecosystem, I got a few doubts:

1. Does it support other languages? If not, is it in the roadmap?

2. Can we expose it to our users so that they can create custom logic? If yes, how do we ensure that their functions do not pose a security risk to our systems? What are other security implications to be kept in mind?

3. How do we test, monitor and trace/log it?

4. Is there a concept of warm/cold in SCF?

5. Can we share libraries among different functions?

6. Can we call a function inside another? How do functions communicate with each other?

7. Can they share memory? How does it handle transactions, persistence, connection pooling, etc?

8. What is the failover mechanism? Does it ensure exactly once semantics for its execution? Does it automatically restart if it died in between an execution?

9. What is the difference between Apache Spark, Spring Cloud Data Flow, Spring Cloud Functions, AWS Lambda/Openwhisk when seen from the perspective of an application developer(writing business logic)?

10. Openwhisk has support for workflows. How does the provided SCF Openwhisk adapter handle such cases?