How compliant is Mendix with BPEL and BPMN? The microflows I create in Mendix can be exported to generic BPEL or BPMN? And can the generated code be directly imported by other tools? Additionally, can the BPEL/ BPMN generated by other tools be imported to Mendix?
Mendix doesn't generate code. The microflows which are built in the modeler are interpreted by the mendix business server. So the MDP which is created in your deployment archive, will be interpreted by the business server.
The microflows which are created by mendix cannot be imported by another tool, AFAIK.