It was an RF board on the 360. There's no RF stuff on that board at all.
your partition sizes are wrong because you used OS X, which uses base 10 for sizes.
The blu ray drive is not likely replaceable. The Xbox 360 dvd drive used a DVD key to lock one drive to one mainboard. It will take some time before someone figures out how to get around this on the XBone.
The precarious wire is a wifi antenna cable. If you look where it goes, it comes from right underneath the wifi section of the board and goes to near the far away wifi antenna is. You can see where it comes through the board on the side far away form the wifi section, and that it goes to an antenna connection and other passives.
It's not precarious at all, it's soldered in many places to the board to hold it in place (I wouldn't be surprised if all of those connections were connecting the shield of the cable to ground on the board.) That's a really which quality job for the wifi antenna.
Differences between this and the CR48 touchpad controller?