Team Photo Composite Editing

I have a high-resolution team photo in JPEG format taken against an outdoor backdrop. I need to retouch the lineup so it looks as if the shot were taken that way originally: two existing team members should disappear completely, one remaining person needs to slide into a new position to balance the composition, and a new colleague must be inserted seamlessly from a separate image that I will supply.

Please match ambient lighting, natural shadows, color grading, and overall depth of field so there are no tell-tale signs of manipulation. The final file should be returned in layered PSD (for any future tweaks) plus a flattened print-ready JPEG at the photo’s original resolution.