I'm not a security expert so I select the default OpenSSL settings.
Too complex to implement for now. It is good that another module implements this method.
Errors are reported by exceptions.
Too complex to implement for now. It is good that another module implements a callback for OCSP stapling.
Too complex to implement for now. It is good that another module implements a callback for SSL session.
Too complex to implement them for now. It is good to use Net::SSLeay object directly.
Generally, NPN is not recommended.