I'm not a drag racer, but I think I can help!
Brakes would be very simmilar. You NEED good brakes and the hyd kart style brakes work very well.
Steering I'm not sure you would need as fast of steering as we use, and I'm not sure you would want it that way. If your a drag racer you know that you don't want quick steering. We need quicker steering because we have to turn to make laps.
I'd look in to the Jr Dragster parts for steering stuff. I know ARC makes a very nice rack and pinion set up for Jr. Dragsters. I'd recommend using one of them as you will NEVER wear it out and your kids would be safe.
Good luck
Paul