Yes, arduino should be able to do all that except for the audio, to which I don't quite know the answer. Could you just strap a two way radio on the robot?
Don't you want suggestions on sensors? The robot can't be blind muscles, right? I suggest ping sonic ranger and an IR distance sensor.
We're planning on having it teleoperated. We originally considered automating it, but considering the time constraints and that we need to design both mechanics and controls of the system we decided it was best to keep it simple. The current idea is to use a Wifi supported security camera in order to see where the robot is driving, and the audio would aid in the virtual presence portion of the robot. The audio is probably our least concern since it's a secondary function that our professor insists on (as if running analysis and teaching yourself how to build a robot wasn't enough). I actually joking thought to myself about the two way radio, and it may end up coming down to that.
I'm mainly looking for suggestions on controllers, motors, and ideas on implementation. I'm planning on 12V motors as of right now, but I don't have anything picked. The entire system will probably weigh about 30-35 lbs, or at least that is the target, with a footprint of approximately 12"x18".