There is a vacuum port 2nd picture right under the airfliter. It is capped with a black cover, loooks like it is on the metering block. Also another source is where your vacuum advance for your distributor. You should also have a tap on the manifold inbetween the carb and the dist.
On my Holley carb there is a full manifold vacuum port right next to the PVC vacuum connection. Not sure if all Holley's are the same though. I would go to the Holley web site as it has online manuals for most of their carbs.
Nope. Those are just threaded bosses for mounting stuff.
Like ranger and lingo both suggested, Chevy intakes often have a plugged port behind the carb. It's a common place to get brake booster vacuum. If your Edelbrock has it you can replace the plug with a barbed fitting and be good to go.