Five screens, each its own page for its own device, running as one system. Something you do on one shows up on the others right away: the kiosk order lands in the back room, the shelf number lights up the big screen and texts the customer.
Connecting…Every page is a web app. Open it on its own device, then add it to the home screen. It opens full screen with no browser bar, with its own icon.
Each code is both a QR code and a barcode for the same shoe, size and color. Frame just one code about 20 to 30 cm from the phone.