You are welcome to post your sketch on the public forum but but please don’t PM it to me. If you post publicly other people might be able to assist and/or other users might benefit from the discussion. Unfortunately I do not have the time available to offer one-to-one support.
Have you done anything on the pi to connect to the arduinos?
If you look at your emonhub.conf there is a section called [[rfm2pi]], this is an “interfacer” configuration for the emonpi or rfm2pi add-on boards attached to the pi’s gpio serial port. You can see that interfacer being created in your emonhub.log images. You will need similar configurations for each of the arduinos if you want emonhub to set up a usb/serial port and communicate with them.
There are 2 existing interfacer types to do this, one is specifically for the emonTx v3.4 firmware and the other is a more generic type.
You can find more info here on the forums by searching terms like “serial-direct”, “emonhubserialinterfacer” and “serialtx3e” etc
You should also take a look at the openenergymonitor/emonhub github repo directserial-serialtx3e and directserial examples.
The Does the emonTx Shield need an actual Arduino? thread might be useful too.
In that thread there is also info about creating udev rules so that the arduinos can be uniquely identified otherwise you may find they can swap addresses (/dev/ttyUSB0 and /dev/ttyUSB1 etc) but if you opt for the serial-direct (not tx3e) format the node id is passed within the payload to the addressing is not an issue.
The 2 serial formats are quite different, you can choose to use either as long as you use the correct interfacer type to decode the payload sent by your arduino’s.
I hope this points you in the right direction, feel free to ask questions and we can try to help you, but most if not all the info you need is here on the forums in abundance.