If you're pumping the gas up and no fuel is getting through you likely have a stuck metering needle. I've had that happen sometimes. Pull the cover and take out the needle and clean it up and make sure it's not sticking down. If you put a new kit in it, try the old needle if it still sticks. Failing that give the carb a good soak in Sea Foam.
As far as the tank vent goes, is there no hole in the tank as it shows on the IPL?
When I did the carb the 1st time everthing looked so good I didn't pull the metering needle. I did the 2nd time, all diaphragms looked and felt good so I haven't added a kit.
I have used the Sea foam trick in the past, recommended by you, successfully. There is no hole in the fuel tank that I can see, certainly not where the ipl shows it. Doesn't seem to be any type of breather in the fuel cap either.