[Jon Stratis]

Be wary of a rule like 2014's R71:

All outputs from CUSTOM CIRCUITS shall connect to only the following:

other CUSTOM CIRCUITS,
input ports on the Digital Sidecar,
input ports on the Analog Breakout Board,
the RS-232 port on the cRIO,
the Ethernet network connected to either Port 1 or Port 2 of the cRIO,
the CAN-bus if and only if all Jaguar motor controllers on the CAN-bus are wired in full compliance with R67and R68, or
the sensor inputs on the Jaguar motor controller.

As an LRI, I would probably call your description (having not seen it and not having next years rules in front of me, I can't make a definitive ruling) a custom circuit - even if the latching connectors are just pass-throughs, I would need a Q&A to allow it AND time with the bare circuit to verify it. It would be better to limit yourself to a circuit on the MPX with some plastic latching features that extend out to the other IO without actually interfacing with the IO pins, similar to the latches that extended up and over the lip of the PWM cables on the DSC and breakout boards.