You could certainly use tank circuits to compensate for the peaks caused by mechanical and Helmholtz resonances. But such a filter will also change overall system tuning, so you would need to look at that and analyze the system as a whole.Zobels and plain shunt resistance are dampers that will help with the tank circuit formed by interaction of the voice-coil and the crossover capacitors. They'll obviously have some effect on mechanical resonance too. But a Zobel will have very little effect because its impedance is high at low frequencies. And a shunt resistance will not damp mechanical resonance much either unless the value is prohibitively low.