So I've unloaded everything except MJ, and it is now running. I started loading my other mods back one at a time, and it appears that including Firespitter was where the problem started again. The player.log file from the console ~Library/is below.
I was able to load the game with every single mod I've ever downloaded, minus MJ, so it would seem that the issue is between MJ and Firespitter, which stinks, because that means no USI until it gets fixed.
https://www.dropbox.com/s/535ose5ejo3jruy/Player.log?dl=0