| What kind of rep ranges you working with? I would go in the 10-15 range honestly.
With squats, is it that you're worried about putting the bar on your back? If so, you'll soon realize that the bar is resting across your shoulders. Give it a shot with just a barbell. See how it feels.
Leg extensions < Lunges
Thats quite a few exercises, some which I personally dont prefer such as Upright Rows, dips, and calf raises. Look into the deadlift, I find them to be one of the more fun exercises. | 
