Hey @jepyto - yup the KDS works for any transactions within Square.
Most of my pizza orders come in online and I tend to use the standard POS for walk ups. All shows up perfectly on the KDS.
The only thing I'm not 100% sure of is if you can enter a ticket name on the Retails POS system - but if you've been using paper tickets this will just be the same as now in any case.