Just thought I'd update as a community service. It appears that (for whatever reason) the Whiteline Lower Control Arm Relocation brackets MAY NOT work without adjustable control arms. I'm not going to say they WON'T work, but Whiteline has in essence blamed my Roush LCAs for the change in my rear axle...even though I proved to them that the axle was fine after removing their brackets.
Regardless, I sent them back and their techs said the brackets were perfect, so I can only assume there is some small difference that makes these not compatible with a 2014 GT with stock length LCAs. Luckily they have allowed me to get my money back from CJ's Pony Parts.