You tried a lot of different settings in that log, but I'll go by the last one as I assume that's where you left it.
The biggest issue I see is that you're using a medium encoder preset. Change it back to veryfast. Your CPU will not be able to stream with the medium preset.
And if you're not going to enforce streaming service settings you need to manually set the keyframe interval to 2 seconds if you're streaming to Twitch. Your setting right now on auto is ~8 seconds.
And you don't need to rescale the output in the streaming tab. Uncheck that, and change it to 1280x720 in your Video settings.
And plug in a network cable to your router. Wireless is not recommended for streaming.
... And
read sticky threads ;)