If the timing is sufficiently different between the slaved and the master LCD, then it may become necessary to interpose an MCU. However, since an MCU is operating the master LCD, the time-lag resulting from the fact that most MCU's operate at a leisurely pace, it's unlikely that the signaling reconstructed at the remote LCD modules will be enough of a "strain" for the LCD, even with somewhat slower oscillators. Since LCD's don't always monitor the busy flag, they must all adhere fairly closely to specified timing. The slaves will NEVER be read, so that's certainly not a factor.

The CPLD should ignore all read operations, which it can easily do.

RE