That's currently the ship root block, yes. I think I will change it to the actual center of mass.
I thought of a grid for the block size when you scale it. I think that'd do the job?
It would be, yes. It's a little more complicated than the asteroids, as those are currently indestructible and wreckages are not. This has to do with rendering optimizations. Also, wreckages can be salvaged - And you get a hell of a lot more out of them then out of asteroids, so it could be a balancing issue.
Yup, why not?
I guess positioning the camera for the corresponding block could be difficult - other than that it would be possible.
That's a feature to come, haven't had time for it yet.
I had something similar in mind. There are already categories, that can be assigned by scripts. But those are mostly meant for types of ships/stations, like shipyards, transporters etc.
Overall those are quite easy to implement features, I think they might one day find their way into the game!