What is essential when analyzing «وَأَمَّا ثَمُودُ فَهَدَيْنَاهُمْ»?

Fronting the Object: Correction, Restriction and Ordering of Complements

• Accounting for ammā, the fāʾ and the pronoun
• Treating every noun after ammā as an accusative object
• Treating the fāʾ as invariably superfluous
• Taking the response as a relative clause