Graviman
Steady - you're getting a bit technical here for us mortal pilots. However I think that what you are describing as "compliance control mounting" is more like what is fitted to the EH101 family - ie active struts attaching the transmission to the airframe. This is a reasonably elegant solution as it removes the vibration before it reaches the airframe, but is not a simple (hence cheap or light) solution as these same struts carry all the lifting forces for the airframe, plus as you say there are problems with the interface between airframe and transmission eg flight control pushrods and engines. Someone flying these beasts might tell us more.
In comparison, the active vib systems on the 92 and 225 are relatively simple in that there are no dire consequences of failure modes, and certainly in the case of the 225 its just the icing on the cake as its already a smooth aircraft.
Generally the actuators are mounted on the cabin walls, and of course the anti-vibe effect is fairly localised. Not sure where the accelerometers are, but surely they shouldn't be right next to the generators because they are predictive - the great advantage of helicopter is that the rotor rpm is (hopefully) constant, and the flight regime changes relatively slowly - and if they are some way away from the generators that is likely to increase the sphere of vibration reduction.
Better stop now 'cause you can tell I barely know what I am talking about!
HC