Is the free parking near the amc burbank 16 usually full on weekends before the 4pm hour? how about at night?

You can usually find a spot in a couple of free parking garages near there before 4 pm on the weekends. On weekend nights, you can still find it, but it's more difficult. You will find it, but you might rip your hair out waiting behind people in the garages waiting for spots and stopping traffic. Arrive VERY early.