Make sure all the cameras are EX-1 cameras and not a mixture of EX-1R and ex-1 cameras. The latest firmware is different. The ex-1R cameras will more than likely work with the large cards if the firmware is up to date.
I would check each camera with the card that you are going to use on the shoot and to see if the camera will read and write to that particular card.
I had my PMW 320 which uses the same card as the EX cameras to go down when it switched slots to a large card because of the firmware update was not current. One other thing, (just to be sure that the cards have reliability) I would make sure that they are all the "pro" cards rather than a mixture of SXS-1 the SXS pro cards.
Best option is the look at the firmware versions of each camera and call Sony service in NJ.
Hope this helps.
Kato Video Productions