Question:
For the electronics team, what is required in terms of a concept sketch?

Answer:
For these two teams I am going to be very open-minded.

You may develop concepts about how to run the wiring.
Although that is kind of simple.

If your preliminary analysis shows that batteries need
frequent replacement, you develop concepts on how that can be
done. It is an electronics issue but it does cross over
into chassis design.

You may present a concept for an Electrical Control System
For this go speak to Mr. Brownell. He can show you one concept
and can tell you about what information the concept relays.

Your system will have a primary electrical power supply. It
may be a 12V battery for example. Many of your components will
need either a greater or lesser voltage. So you can present
concepts for voltage multipliers or dividers.

Many things in your system are of a relatively high power
in comparison to what a microcontroller can tolerate, like DC motors.
You may present concepts on how you would turn a DC moto
on and off with a low power signal seen from a microcontroller?

Likewise you can present concepts on how you control a servo
motor based on a low power signal from a microcontroller.

On the input side. You may want to design a circuit that allows
a signal received from a touch sensor to be input to the microcontroller.

Present a concept for the circuitry involved with PWM speed control of
a brushed DC motor.

Present a concept for s circuit used to speed control a motor incorporating
optical shaft encoders for feedback. Suppose you want two motors to 
turn at the same speed (going in a stright line). How do you get
that to happen? If you apply the voltage to two identical motors, they
will not rotate at the same speed, even though they should. They have
slight differences in their construction.