Hi Macguru, those are some good questions.
I did spend a lot of time researching all the possible options before I went for this. In all the searching that i have done, i have never found an m.2 WiFi module that has the M socket. As far as i can tell, they are all E socket, or A & E socket.
Unfortunately this hack will not get Bluetooth working. Bluetooth does not run over PCIe. It runs over USB. There is no USB connection on the m.2 M socket. (You would need a proper E socket on the logic board).
You could swap the SSD and WiFi around to make the cables shorter, that would be a neat solution. However, i am fairly sure that the secondary m.2 slot only has 2x PCIe lanes, while the primary m.2 slot has 4x PCIe lanes. This means that you will see much slower SSD performance if you move it to the secondary m.2 slot. I might be mistaken, but i thought i read that somewhere. Maybe somebody else on the forum can confirm if that it correct or not?