You may need the tweak because what you have is no longer working.
Quit muddling the basic issue with all those other Port forwarded things.
4G irrelevant,
Blutooth (other than one with a IP FTP channel) irrelevant
That may come in way later. You proved you rig has some network access
move on and nail the basic problem of 127.0.0.1
Basic Troubleshooting:
You first need to solve WHY calibre is on the wrong IP
If it is not accessible ON YOUR LAN, it sure ain't gonna be from the WAN.
Fix the first problem and you may find the rest just works.
Your rig has multiple network devices, so you may need to use the tweak to steer it. Theory says it should not matter.
If the theory was perfect, the tweak would not be there .
what does the
netstat command (or a gui network status tool) turn up?
Lots of Macs running out there on the current version (14% of the Calibre users use OSX). If there was a problem, we would see more help requests here.
This is something unusual with your rigs configuration.
Have you tried renaming the Calibre Config folder (so it regenerates)?