Firewall Openings

[Zombie666]

Just trying to figure what some of these holes are for. Just want to be sure before I seal them up or use it for something else and then realize I needed it.

1. The two large openings are for steering column and fuse block.
2. Just below the steering could opening is a small hole?? What sis this one for?
3. Upper right corner of photo is a square hole??

Thanks in advance.
Perry