I'll admit... you lost me!
Have you had any luck with this?
As a starting point, I would suggest running the wireless receiver as follows...
1. Output of the Wireless to GCX #1 Rear Panel Feedthru.
2. GCX #1 Front Panel Feedthru to GCX #2 Guitar In.
3. GCX #2 Rear Panel Guitar Out to GCX #1 Loop 1 In.
4. GCX #2 Rear Panel Feedthru to GCX #2 Loop 1 In.
This will allow you to send the wireless signal to both of you effects chains and have the ability to plug in using a cable in case the wireless goes down for some reason... simply pull the cable going to the GCX #2 Guitar In and plug your bass in to bypass the wireless.
After that, well that is where I get lost
I think you are attempting to use the LS-2s in place of a mixer maybe?