Computers run on electricity. If you plan to do something with Arduino, teaching them voltage, resistance and current is important for them to move forward on their own. Also, it's good to be taught about the dangers of it... so they don't attempt anything that may endanger them.
Logics is ok, although analog might be tough if you don't give them good bases in electricity and basic electronic components. I guess a must is at least to connect a transistor to spin a motor or turn on a relay.
It's not easy... but you have quite a flexible task without any limitations on what you need to teach. So like with everything else, be sure to teach the basics so they can fully understand them and take it from there.