You can't connect the FCB to the UX2.
You would connect the UM1 to the FCB, then connect the UM1 and the UX2 to your computer's USB ports.
To save USB ports you could try using a hub, but hubs are iffy, might work, might not.
In GR5 Standalone you'll need to select the UX2 for Audio and the UM1 for MIDI.
to use GR5 as a Plug-In in Reaper you'll need to make the same selections in Reaper Audio and MIDI Preferences.
You'd then create an Audio Track with GR5, and a MIDI track with the UM1 as Input and the GR5 Track as Output.