Also, I'm a little confused on my usage of I2CWrite...

According to the DAC's datasheet, the first byte sent needs to be the address byte which is 1001(A2,A1,A0)W which is programmed to 000, so 1001000W. Then the control byte is sent and stored in the control register, which flags the analog output, and sets everything else to 0 (01000000). The I2CWrite definition, however, sends the "Control" first and the optional Address out second, followed by the value. ??