How to check the port usage

Yes 1 consumer and 1 producer, you produce from one router and consume on another router so it 1 producer, 1 consumer is involved in pipetransport on the routers respectively. Check my topic regarding this for clarification:

I am not aware of such thing and you don’t need to observe it, just go with max producers/consumers per worker as per you machine and then estimate the rest from it.

Yes it is ok.

This is subjective to the machine you are using, check this topic for further clarification: