The Tsunami used by Bachmann is a dumbed-down version of the Tsunami - it doesn't have all the features of the full version. The full version Tsunami and micro-Tsunami have provisions for input from cams to synchronize the chuff. Without the cam, synchronization is achieved by back emf sensing and knowing the gear ratio. But this doesn't mean the chuff is correct for drive rod position. At moderate to high speeds, the chuff becomes pretty blurred, and synchronization becomes less important.
There is a lot of tuning possible with the Tsunami to customize the sound through fiddling with the CVs; less with the Bachmann Tsunami. Some of my HOn3 friends change just about everything to get it to their tastes.
I'm sure the Bachmann Tsunami will work just fine with your EZ Command - Bachmann has a vested interest in making their components work well together. But the EZ Command is limited in how many functions can be used, and does not have the ability to read or write CVs. So you can only use the Tsunami's defaults as assigned by Bachmann with the EZ Command.
just my thoughts