Statement of suitability - should I just focus on essential criteria or behaviours as well?

Title. Should I evidence behaviour statments when writing my statement of suitability, or focus solely on the essential criteria? Most jobs only say essential criteria.

Same question for technical questions in applications which need a 500 word response. I've seen one or two where a technical question is asked but it's not made clear what the technical skil being assessed is - albeit the question gives a hint (eg 'managing a social media campaign - with the objectives, the strategies, and tools you employed, and the results achieved.' - which as far as I'm concerned is all the GCS competencies at once).