Rcs thrusters
Please provide evidence of where the RCS thrusters were placed & how they functioned.
and fins
Grid Fins you mean?
Funny, cos one of the established problems of 'grid fins' is that they DO NOT function at transonic velocities due to shockwave build-up.
So, as sonic booms occur at transonic velocities, your 'assumption' that the descent of your shpayze-rokkit would be 'controlled' is looking rather unlikely.
Of course, when the stabilising fins of any missile malfunction, what occurs is known as a 'tumble'; i.e. it falls arse over tip, loses control & crashes...
Guess SpaceX are 'special', eh?
LOL!!!