Just to clarify, the Icom network protocol has no provision for USB ‘B’ data, so it would need Icom to modify their protocol (which is extremely unlikely)
What information would you get from port B? Maybe there is a way to get it over the CI-V interface. There are hundreds of GPS-related commands on the 705 which we aren’t using at this time (you can send them via the virtual serial port of wfview).