Above the cpu fan is not a good place in my opinion. That's where the fan gets its air from and it cant with something that close to it. I dont know the case and cant tell the dimensions from the pics but how about the drive in the middle either on its side or flat screwed to the lid. Another option I can maybe see is put the M2 in the middle attatched to the lid and the drive up front. The sound card is really very thick so there should be quite a bit of room to the side of it.
Edit that should read isn't really very thick if you hadn't worked that out.