I calculated the needed wires for the whole system. Because the electrical outlets are in the other end of the floor trim, the continous ledstrip + wire would be around 10 meters. 8 separate led strips and 6 ultrasonic sensor for the doorways. Each Ultrasonic sensor needs a separate trigger and echo line (quick googling to prove it), the led strip needs common GND, common +5V + a separate data line. In total I would need 22 separate wires to get all the data across to the arduino. I would need a big cable duct to keep all wires in and the setup would be prone to failure. Not a good idea...

The ESPs aren't that expensive and the "new" ESP-12E has all the needed GPIOs to get things working. I could setup one ESP + ultrasonic sensor + led strip as one module. The modules would only need +5V and GND if I added one 3.3 voltage regulator to each module. No idea if the ESP8266 is up for the task, but testing will prove it.