Using an analog demultiplexer as a digital demultiplexer
Only if an input could be left floating. For example, if you select between several outputs to a single input, all analog inputs are tied to something (or you believe they can never be selected) and the mux is always enabled then you don't need a resistor.

Chances are that if you are using it as a digital de-multiplexer this condition won't be true and you need one resistor per mux output.

Also keep in mind that the switch-off will be relatively sluggish compared to push-pull drive, depending on the resistor value.