Hi, #1 I'm don't remember, and i can't find my old spacer plate, it might be a blind hole.
#2 is a vacuum port for everything besides PCV and distributor vacuum, like automatic transmission modulator or Power brakes.
#3 it for a hot air choke stove.
#4 is for the heater hose. There is also the same opening behind the carb to continue the heater hose to the heater control valve.
I would put washers under the carb nuts.
Visit Fordsix.com and get the Ford Falcon Performance Handbook to get more out of your Ford 200.
Good luck