These exercises are done with maximum weight between 3-5 reps

Bench press:

I understand your elbows should be a 90 degree angle, however, I find unless I don't go all the way down to my chest, this angle is impossible to achieve, any suggestions:

Squats:

If I tore the lateral tendon in my foot doing squats, what foot positioning error am I committing

Leg Press:

If I'm feeling a lot of pressure on my lower back doing these, what is wrong with form or foot placement?

Thanks for your help