2013 Prius C One Illumination and Dimmer Wire Questions

Hello,

I recently swapped the headunit on my 2013 Prius C One. The headunit has a Illumination wire available, but according to the metra wiring harness (70-1761) documentation, the car only provides a dimmer wire. Am I going to have to route a different wire to connect to the illumination wire supplied by the headunit? What would happen if I were to connect the dimmer wire to the illumination wire? Will the dimmer wire supply the necessary voltage required to activate the illumination features provided by the headunit?

Also, since I have your attention, the headunit provides Key1 and Key2 wires, will I need a Metra ASWC-1 for the steeringwheel buttons to work?

Thanks!