So based on the second diagram I am confused. It looks like your av guy is planning to install four IC surrounds PLUS two Atmos height speakers?
Atmos will NOT work if all speakers are in the ceiling. So, if In ceiling is your only choice, stick with 5.1. Also, why is there a pair of surrounds in front of the couch?
Definitely consider other subwoofer options than the Polk hts 12. There’s much better out there.
The AV guy should know better than putting all 6 surround/Atmos speakers in the ceiling, AND put a pair half way across the ceiling well in front of the couch. Seems like a money grab...