Add Realistic Elements to Photo

I have a high-resolution photo that I’d like enhanced by seamlessly inserting a few realistic people / objects into the scene. The goal is a natural, believable composite—lighting, shadows, perspective, and color grading all need to match the original shot so no one can tell the image was altered.

Please work in Photoshop (or equivalent layered editor) and supply both the finished flattened JPG/PNG and the fully editable layered file so I can tweak positions later if needed. Let me know any questions about image size, element sourcing, or reference angles before you begin.