Hey Mike. You don't need to change out the dome light. However if you are wondering about the rear seat audio, RSA's not going to work with the OEM head unit removed. The good 'ol AVC-LAN communication system prevents non-Toyota components from working in the audio-video systems. Same goes with removing components. Remove the OEM headunit, RSA won't work. Neither would RSE if you had it.
Of course, if you change out the head unit, you can always throw in an aftermarket overhead video unit, or headrest monitors to keep the rear seat passengers occupied.