This WAVE would typically be run for how long before changing up movements? Week 4 would be the DELOAD WEEK if I'm not mistaken. Can you explain what is a DELOAD WEEK please?
Yes, every 4th week is a Deload Week. A deload week is where you cut back on your exercises, intensity, and amount lifted.

For your deload week, only perform 3 exercises total so drop one of assisting. Drop the weight to 50% of 1RM and perform 3 sets of 5 reps for ALL movements.

Change the assisting exercises every 2 waves so every 8 weeks. I can make a list to choose from if you would like.