Not sure about "most" (depends on the sample distribution I suppose), but single syllable (i.e. character) words are used much more often relative to Mandarin.

So in general you're probably right. Not sure whether that is a cause of more strict adherence to tones in songs though. It could be alternatively argued that the more complex syllable (due to more tones among other things) in Cantonese allowed it to retain single syllable words without having to add extra syllables to clarify any ambiguities.