PHUL how does progressive overload work

Iam about to start the PHUL program and was wondering 2 things 1. How does progressive overload work on the three main lifts and hypertrophy work. 2. Can I swap out the overhead press press with a seated db shoulder press. Skull crusher with overhead cable extension. Leg press with simple leg extensions. Seated incline curl with Bayesian curl and lunge with a Bulgarian split squat?