Hey Eric, As far as the codes for the tranny go I dont know. I can look in the FSM for ya later on and see what I come up with. But the light problem on the cluster is not the ABS. The little red light that looks like a lamp is not the ABS but the actual lighting system. When that comes on it is saying there is a bulb out or a breakin the circuit. If you replaced your lights ith JDM tails or corner lights and didnt change the bulb that will come on whenever you have the lights on. As far as the ABS itself goes. There is a way to read the codes oeff o the ABS Actuator (Behind the passenger seat) and they will tell you what is wrong with your brakes. Z32 Brakes in general suck. There are alot of people making kits lately so you can use larger rotors from a 350Z or a Skyline. Some are for a decent price as well. If you are not comfortable with your brakes then I would definitly go larger. I hope this helps. I will look in the FSM for the Tranny and ABS Codes. Good luck!
Oh and as far as reading the codes ao the ECU, well thats an easy one!
http://www.ttzd.com/tech/diagnostictech.html
The OBD II did not come out in the Z32 till 96 (hence 280hp v 300hp)
Here is the Tranny Diagnostic
http://www.twinturbo.net/ttnettech/a.../autodiag.html
Try that for the time being. Still looking for the ABS Codes.