hmmm, interesting question. Sounds like a good time to do a couple tests.
1st thing I would do is start a new project, put your very long one hour clip in, and cut it so it's a nice 1 minute clip... one minute. That solves one problem right off the bat.
Now make your proxy. The h264 might be cause of the 4 channel audio as normally it's like 2 channel ( left and right ). So, don't use it. Use your prores thing instead and downscale that only to the export size you want. If you are shooting 8k and will export full HD, it's silly to use a proxy higher than your planned export ( cause you can use the proxy to export and save time ).
I have no clue what your camera is or codec etc. so I don't know what NORMAL would be to debayer and make that linear ( probably different for every platform on earth so there is no normal ). In this case, normal is YOU only. Hence the test.
See how the one minute works out. Make up your mind after that.
And, NO, it has nothing to do with the frame rate ( number of frames per second ) IMO.