I think you need a voltage divider network for the LDR. As it is the voltage on your ADC input line will always be 5VDC.

I also wonder about the capacity of your transistors. The stall current on the some of the motors I found was 46 Amps. If the motor were to stall, your transistors would burn out with unknown consequences. If you want to use this motor I'd put a fuse in the supply line to limit current during stalls.

Typically motors make alotta noise when running. I think it's a great idea to separate the power supplies. Just make sure to make the low side connected between the two systems.

My intimation of TRISIO is relevant to PBP2.6 also. I'm not sure if PBP starts with LSB when reading the TRISIO and quits after 6 bits or starts at the MSB and quits after 6 bits. I do know the 12F683 only has 5 I/O pins and one I only pin so your TRISIO statement should be 6 bits wide.