andy_s
pihole is just a service, you can install it on raspbian just fine.
as for lights, think about addressabel LEDs using ESP8266 & SK6812; that way you can have not only light, but status indication as well (ask me how i know 😉 )
But since you do not have printer running 24/7, having pihole running on this pi is not a good idea, your network would be basically crippled.