AX-Synth and global/all MIDI TX?

Just in case someone else might need it, user xp30 found a solution for it.

On the Roland Fantom, the zone key ranges are controller settings, and not tone generator settings. That will that these settings change the behavior of the local controller, and what MIDI events it sends to the tone generator and to MIDI OUT. These settings are irrelevant for incoming MIDI messages.

There is a special case: There is a "Remote Keyboard Switch" option in the global settings. If this option is enabled, then MIDI messages received via MIDI IN will act like the local controller.

So Menu>System>Midi>Remote Keyboard Switch ON

and you have the best of both worlds:
1. All Scene with corresponding key ranges at your AX-Synth
2. AX-Synths favorite buttons recall specific program changes and they all are initially responding to ZCore user bank, so you might adjust your Fantom(-0) to recall specific patches. PGM Change buttons also work as +/- so I strongly advise to set it at #20 or something so you can dial nearby patches on specified MIDI channel.

And all that within one single switch in global settings! Wonderful!

The only drawback from #1 is that every other MIDI keyboard you add will behave the same, so you may not have your piano sound solo on weighted MIDI keyboard.

Oh and if you decide to go #2 way, I Strongly recommend using TX Channel 2 for AX-Synth so you can access Tone Wheel patches. I presume you will reach them more than piano sounds on keytar :)