GOP Size is the same thing as Keyframe Interval, as far as I know. For the purposes of this thread, they are most certainly the same thing. GOP (without saying size afterwards) isn't the same, that's true. Regardless, when YouTube says "GOP of half the framerate", for x264 encoding you set keyint=x, where x is half the framerate.
bframes = 2 is another setting for YouTube. As is variable bitrate (use CRF instead of 2-pass or CBR).
Your latest log file only shows 26 seconds of capture time. Statistically speaking, I shouldn't make any conclusions on the performance figures contained within. Try capturing 5 minutes of high action scenes.
The setup looks good though. 1080p30, correct custom x264 commands, CRF lowered.