Corporate Photo Enhancement: Add People & Pixel Fix

I have a corporate group photo that needs some enhancement. I need 3-5 people added to the photo, but want the photo to look normal. I have all individual photos of the people to be added. They can be in background if needed. The same 2 girls are each in two attached pics...choose what works best because they are difficult to deal with

Key Tasks:
- Add 3-5 individual photos into the group corporate photo
- Fix the pixels and enhance the overall quality of the photo

Ideal Skills:
- Photo Editing
- Photoshop
- Attention to Detail

Please let me know if you can help with this project.