1. In regard to mental imagery and other lack of qualia phenomena, it seems to me that the lack of qualia can be in the other directions in all cases. For example, people who say that they can form mental images, may not have qualia for real life imagery, so both experiences are more of the same to them.
How you can distinguish between those two possibilities?
2. People without qualia (if exist) will have their “real” interpretation of stuff like “vivid sensation of my own presence”, and i think that most definitions will failed to find them.
And to be more specific to your definition—non-qualia person will still have awareness for his presence and a self. And still will have more awareness for what he think and his body when meditate.
Maybe the incompetence level change.
Yes there are incompetence in the Navy SEAL, but for some one not in the Navy SEAL the incompetence will look like high quality job.
If you are John von Neumann then everyone else seem a little incompetent.