Thanks for the advice, switching the red and yellow wires did the trick! The satellite receiver turned on and I was able to bind it to QGC, and I can finally move forward with this project. Thank goodness you guys are here.
However, I did soon run into another error - when trying to do the radio calibration, I cannot correctly assign the yaw and roll sticks - whenever I move the yaw stick to the location that is prompted (on Mode 2), nothing registers. The calibration only accepts it if I use the right-hand stick, which shouldn't be used for yaw. Do you know what might be going on?