Update lead source and attribution

I need the lead record updated so marketing and the AE see who earns credit. Update the lead source to 'Paid Search - Q3 Google Ads' and set the primary campaign to 'Q3 Brand Push', then add UTM attribution values to the attribution fields. Do this before I hand the lead to Jamie in SDR at 10:30 so commission and pipeline reports are correct.

Before I change the source across 120 leads, make it impossible for someone to miss attribution: surface the current lead source and UTM at the top, highlight mismatches where source and campaign disagree, and flag leads that will change owner if I update source. Suggest a short confirmation message I can show to the user that explains the impact on reporting and pipeline.

I imported 137 leads from a trade form; most display 'Web' with no UTM and they will go to different AEs. I'm afraid I'll break attribution and upset commission splits if I bulk-change them. I can't see which leads actually came from paid search vs organic. What is the most reliable way to reconcile these records, preserve current owner assignments, and fix attribution without losing reporting fidelity?

Across several quarters, our imports and SDR uploads strip UTMs and we keep chasing attribution fixes. This costs hours reconciling reports and costs disputes between marketing and sales. Which habits should we change so lead source stays correct: how to change the import checklist, ownership handoff, and a simple validation step to prevent future mass attribution loss?