Professional Photoshop Family Photo Composite – Preserve Existing Faces

Professional Photoshop compositing of a family photograph
I have one master family photograph plus individual high-resolution photos of approximately 12 family members who need to be integrated into the master photograph.
Critical requirement: preserve the existing people exactly. Do NOT regenerate, de-age, beautify, replace or otherwise alter their faces, ages, clothing or positions.
This should be done using traditional Photoshop layers, masking and manual compositing, NOT AI regeneration of the entire photograph.
Added people must look naturally photographed in the same scene: correct scale, perspective, lighting, colour, shadows, proportions and edge/hair masking.
This is an important family memorial photograph, so facial identity preservation is more important than speed.
I would like to begin with one-person test edit using my actual family photograph.
Please provide examples of your previous family-photo compositing/manipulation work, preferably before/after examples.
Final delivery should include a high-resolution print-ready image and preferably the layered PSD/source file.
Budget: up to ₹9,000, depending on quality.